ALBERT

Description: Direct evidence of the relationship between the polymorphic phase transformation from monoclinic Cu 6 Sn 5 to hexagonal Cu 6 Sn 5 and stress accumulation/release in Cu 6 Sn 5 , formed at the interface between Sn-0.7Cu lead-free solder and their Cu substrates, has been obtained. To explore this challenging phenomenon, we developed an in situ heating/isothermal observation technique in ultrahigh-voltage transmission electron microscopy that enables the observation of thick samples (around 0.5  μ m) for solder joints, including Cu/Cu 3 Sn/Cu 6 Sn 5 /Sn-0.7Cu solder interfaces prepared by a focused ion beam milling technique. The results show evidence of stress creation and release events by imaging bend contours that may arise due to the polymorphic transformations of the Cu 6 Sn 5 phase and the associated volumetric change.

Description: Effects of temperature and slag basicity on the reduction rate of iron oxide in molten synthetic electric arc furnace oxidizing slag by Al-40 wt.%Fe alloy was investigated. An alloy sample was dropped into molten slag in an MgO crucible. When the initial slag temperature was 1723 K, there was no reduction. However, when the initial slag temperature was 1773 K and the slag basicity was 1.1, the reduction was initiated and the temperature of the slag rapidly increased. When the slag basicity was 1.1, increasing the initial slag temperature from 1773 K to 1823 K increases the reaction rate. As the slag basicity increased from 1.1 to 1.4 at 1773 K, the reaction rate increased. From SEM analysis, it was found that an Al 2 O 3 or a spinel phase at the slag-metal interface inhibited the reaction at a lower temperature and a lower slag basicity.

Description: TiN and (Ti,Mg)N thin film coatings were deposited on Ti substrates by an arc-physical vapor deposition technique. The effect of cell presence on hydroxyapatite (HA) formation was investigated using surfaces with four different Mg contents (0, 8.1, 11.31, and 28.49 at.%). Accelerated corrosion above 10 at.% Mg had a negative effect on the performance in terms of both cell proliferation and mineralization. In the absence of cells, Mg-free TiN coatings and low-Mg (8.1 at.%)-doped (Ti,Mg)N surfaces led to an early HA deposition (after 7 days and 14 days, respectively) in cell culture medium (DMEM), but the crystallinity was low. More crystalline HA structures were obtained in the presence of the cells. HA deposits with an ideal Ca/P ratio were obtained at least a week earlier, at day 14, in TiN and low-Mg (8.1 at.%)-doped (Ti,Mg)N compared with that of high-Mg-containing surfaces (〉10 at.%). A thicker mineralized matrix was formed on low-Mg (8.1 at.%)-doped (Ti,Mg)N relative to that of the TiN sample. Low-Mg doping (〈10 at.%) into TiN coatings resulted in better cell proliferation and thicker mineralized matrix formation, so it could be a promising alternative for hard tissue applications.

Description: The content of TiO 2 has an important influence on both the basic structure and the crystallization behavior of titanium-bearing blast furnace (BF) slag. The results of thermodynamic calculations show that, when the mass content of TiO 2 is smaller than 25%, CaTiO 3 increases as the content of TiO 2 increases. However, when the TiO 2 content is more than 25%, the CaTiO 3 content decreases and TiO 2 gradually increases. The results of a confocal laser scanning microscopy (CLSM) experiment show that, when the TiO 2 mass content is 10%, Ca 2 MgSi 2 O 7 and Ca 2 Al 2 SiO 7 are the main crystallized phases resulting from the molten slag. Furthermore, when the TiO 2 mass content is 20%, CaMgSi 2 O 6 , Ca(Ti,Mg,Al)(Si,Al) 2 O 7 and dendrite CaTiO 3 are the crystallized phases, while when the TiO 2 mass content increases to 30%, CaTiO 3 is the sole phase. The discrepancy between the CLSM results and the thermodynamic calculations occurs mainly due to the high melting point of the titanium-bearing BF slag. During the cooling process for the molten slag, CaTiO 3 is crystallized first, due to its high crystallization temperature. Furthermore, the molten slag is solidified in its entirety before the other phases crystallize.

Description: Forest-derived biomaterials can play an integral role in a sustainable and renewable future. Research across a range of disciplines is required to develop the knowledge necessary to overcome the challenges of incorporating more renewable forest resources in materials, chemicals, and fuels. We focus on wood specifically because in our view, better characterization of wood as a raw material and as a feedstock will lead to its increased utilization. We first give an overview of wood structure and chemical composition and then highlight current topics in forest products research, including (1) industrial chemicals, biofuels, and energy from woody materials; (2) wood-based activated carbon and carbon nanostructures; (3) development of improved wood protection treatments; (4) massive timber construction; (5) wood as a bioinspiring material; and (6) atomic simulations of wood polymers. We conclude with a discussion of the sustainability of wood as a renewable forest resource.

Description: The AA7050 alloy strips can be successfully prepared by semi-solid powder rolling. The effect and factors of particle size on the microstructure, relative density, and mechanical properties were discussed. The results show that coarse starting powders require less liquid to achieve high relative density, and the formed strips have lower elongation compared with that prepared with the fine starting powders. The strength is more related to defects, whereas elongation partially depends on the grain size. Additionally, the fracture mechanism of strips prepared with fine powders is the ductile fracture because many dimples are observed. For relative density, when the initial liquid fraction is lower than 10%, the difference of deformation degree is the main factor. When the liquid fraction is higher than 10–20%, premature solidification and more particle interfaces are the two main factors.

Description: Based on FACTSage® software, this paper focuses on the thermodynamic calculations of selective carbothermal reactions of vanadium-bearing titanomagnetite concentrates for preparing iron-based wear-resistant material directly from vanadium-bearing titanomagnetite concentrates. The calculations show that it was most likely to generate metallic iron, titanium carbide and vanadium carbide among all possible carbothermal reactions of vanadium-bearing titanomagnetite concentrates in a vacuum of 10 Pa. The equilibrium composition calculations indicate that Fe 3 O 4 can be reduced to metallic iron by carbon above 400°C, FeTiO 3 can be converted into TiC by carbon above 800°C and V 2 O 5 can be converted into VC by carbon above 600°C in a vacuum of 10 Pa. The investigations demonstrated that the percentage of ferrous oxides reduced to metallic iron was about 96%, the conversion percentage of FeTiO 3 into TiC was about 75% and the conversion percentage of V 2 O 5 into VC was about 94% after the selective carbothermal reactions of vanadium-bearing titanomagnetite concentrates at 1300°C for 3 h in a vacuum of 10 Pa.

Description: Cellulose nanomaterials (CNs) are a new class of cellulose particles with properties and functionalities distinct from molecular cellulose and wood pulp, and as a result, they are being developed for applications that were once thought impossible for cellulosic materials. Momentum is growing in CN research and development, and commercialization in this field is happening because of the unique combination of characteristics (e.g., high mechanical properties, sustainability, and large-scale production potential) and utility across a broad spectrum of material applications (e.g. as an additive, self-sustaining structures, and template structures) that CNs offer. Despite the challenges typical for materials development, CN and near-CN production is ramping up with pilot scale to industry demonstration trials, and the first commercial products are starting to hit the marketplace. This review provides a broad overview of CNs and their capabilities that are enabling new application areas for cellulose-based materials.

Description: Novel kinds of nanocomposites based on bisphenol A-aniline based polybenzoxazine matrix P(BA-a) and 0 wt.%–20 wt.% boron carbide (B 4 C) nanoparticles were produced and their properties were evaluated in terms of the nano-B 4 C content. The thermal conductivity of the P(BA-a) matrix was improved approximately three times from 0.18 W/m K to 0.86 W/m K at 20 wt.% nano-B 4 C loading, while its coefficient of thermal expansion (CTE) was deceased by 47% with the same nanofiller content. The microhardness properties were significantly improved by adding the B 4 C nanoparticles. At 20 wt.% of nano-B 4 C content, dynamic mechanical analysis (DMA) revealed a marked increase in the storage modulus and the glass transition temperature ( T g ) of the nanocomposites, reaching 3.9 GPa and 204°C, respectively. Hot water uptake tests showed that the water-resistance of the polybenzoxazine matrix was increased by filling with nano-B 4 C nano-filler. The morphological analysis reflected that the improvements obtained in the mechanical and thermal properties are related to the uniform dispersion of the nano-B 4 C particles and their strong adhesion to the P(BA-a) matrix.

Description: This article investigates the development of porosity in titania-rich slag obtained by sintering via conventional and thermal plasma heating at 1000°C in inert atmosphere. The holder in the plasma reactor acted as the discharge anode confined within a hollow graphite cathode. Quantitative evaluation of the porosity in the conventionally sintered and plasma-sintered titania-rich slag was performed via pycnometry. Specifically, the physical dimension and morphology of the pores were characterized according to the area fraction, mean diameter, shape factor, and elongation factor. Under both conventional and thermal plasma heating conditions, porosity developed on the surface of titania-rich slag. The titania-rich slag obtained by two processes showed different porosity features in terms of the morphology and porosity. A lower porosity was observed in the plasma-sintered sample when compared with that obtained via conventional heating.

Description: The solubility of lithium metal in molten LiCl–Li 2 O mixtures has been measured at various concentrations of Li 2 O ranging from 0 wt.% to 2.7 wt.% at a temperature of approximately 670–680°C. After contacting molten lithium with molten LiCl–Li 2 O for several hours to achieve equilibrium saturation, samples were taken by freezing the salt onto a room-temperature steel rod and dissolving in water for analysis. Both volume of hydrogen gas generated and volume of titrated HCl were measured to investigate two different approaches to calculating the lithium concentration. There appeared to be no effect of Li 2 O concentration on the Li solubility in the salt. But the results vary between different methods of deducing the amount of dissolved Li. The H 2 collection method is recommended, but care must be taken to ensure all of the H 2 has been included.

Description: Analyzing the temperature evolution in pressureless mold-assisted flash sintering, we found the same onset condition as in standard flash sintering: When sample's DC or AC Joule heating replaces environment's radiation heating as the dominant power input term, thermal runaway ensues. Various serial and parallel components connected to the sample, including the mold, insulation, and punches, can affect Joule heating and conduction heat loss, thus play an important role in successful mold-assisted flash sintering.

Description: This work reports the processing steps of Al 2 O 3 (1–5 vol%) nanoparticulate ( d V.50 = 13 nm) LZS glass–ceramic matrix (19.58Li 2 O·11.10ZrO 2 ·69.32SiO 2 , mol%, d v.50 = 3.5 μm) composites for production of multilayered materials with thermal expansion gradients obtained by tape casting. Suspensions were prepared in water to solids contents ranging from 40 to 47 vol% using ammonium polyacrylate as a deflocculant, and an acrylic copolymer and polyvinyl alcohol as binders. Optimum performance was achieved by sonication and controlling the rheological properties for every step of the process. To prepare the composites, different concentrations (1, 2.5 and 5 vol%) of nanoalumina were added to fresh, as-prepared LZS suspensions, by changing the solid contents as required to maintain similar viscosities. Green tapes with high uniformity, without macroscopic defects and easy to handle were sintered to relative densities between 89% and 94%. Dense and homogeneous laminates with gradual composition with increasing concentrations of alumina were obtained.

Description: A new lead-free perovskite solid solution (1− x )BaTiO 3 – x Bi(Mg 1/2 Zr 1/2 )O 3 with morphotropic phase boundary (MPB) has been developed, and its structural and dielectric properties have been investigated. Rietveld structural analysis of the X-ray diffraction data suggest a composition-dependent tetragonal ( P 4 mm ) to cubic ( ) phase transition with an intermediate, phase coexistence region, demarcating the MPB. The compositions with x ≤ 0.05 are tetragonal in the P 4 mm space group and the compositions with x ≥ 0.25 are cubic in the space group. Coexistence of monoclinic phase (space group Cm ) with tetragonal/cubic phase (space group P 4 mm / ) is observed in the MPB region for the compositions with 0.10 ≤ x ≤ 0.22. The temperature dependence of permittivity exhibits a nonrelaxor type diffuse phase transition for all the compositions across the MPB.

Description: The amorphous silica (a-SiO 2 ) and germania (a-GeO 2 ) have a wide range of applications in glass industry. Based on a previously constructed near-perfect continuous random network model with 1296 atoms and periodic boundary conditions, we extend our study to amorphous Si 1− x Ge x O 2 models of homogeneous random substitution of Si by Ge with x ranging from 0 to 1. We have calculated the structural, electronic, mechanical, and optical properties for the series by using the first-principles density functional theory methods. The x -dependence of the variations in the properties is analyzed and critically compared with available experimental data. The mass density, volume, total bond order density, bulk mechanical properties, and refractive index are found to vary linearly as a function of x . For x = 0.5, we have also constructed six different kinds of particle immersion models to test the effect of inclusion of spherical particles of one glass of different sizes in the medium of the other glass on their physical properties. It is shown that particle sizes do affect the properties of particle immersion. Our calculations provide deep insight on the properties of mixture and nanocomposites of a-SiO 2 and a-GeO 2 glasses.

Description: Hertzian testing is applied to obtain flaw distributions in two fusion-drawn glasses and two glass-ceramics. A tungsten carbide sphere (diameter either 1.0, 2.5, or 5.0 mm) was used to produce surface cracks (ring cracks and cone cracks). Two theoretical approaches were employed to describe the data. Both approaches are only descriptive for very high strength materials in which the surface flaw sizes are small (e.g., 〈1 μm). In the first, a Weibull distribution for strength was assumed, and an expression for the probability of fracture was derived based on the stress field around the indent contact area. The unique aspect of this is that the stress field used includes material that has been “probed” at loads below the fracture load. A Weibull plot with this expression shows a slope of m + 2, where m is the conventional Weibull modulus. For the four different materials, the Weibull modulus varied between 8.0 for β-quartz glass-ceramic to 14.2 for fusion drawn alumni silicate glass. The second theoretical approach employs a modification of the method of Poloniecki and Wilshaw (the PW Method) to describe the distributions of very small flaws. The modification removes the need to bin the flaw distribution data. The modified PW Method revealed distinct differences in the flaw distributions between the four materials. These differences are consistent with the different Weibull moduli determined by ranking the different materials according to flaw size. However, Hertzian testing only probes relatively small flaw sizes and thus may differ from typical tensile or bending tests; nevertheless, the method should be applicable for extremely high strength materials.

Description: A strain-induced structural phase transition and its subsequent effect on the piezoelectric properties of BZT-BCT– x CeO 2 ( x  = 0–0.1 wt%) ceramics have been reported in this manuscript. BZT-BCT– x  wt% CeO 2 lead-free piezoceramics were successfully been prepared using sol–gel method. X-ray diffraction spectra of BZT-BCT– x  wt% CeO 2 ( x  = 0–0.10 wt%) ceramics showed a purely single-phase perovskite structure and a change in crystal structure between tetragonal and rhombohedral phases with increasing CeO 2 content. The strain-induced structural phase transition has resulted in excellent piezoelectric properties, d 33  = 673 pC/N, k p ~ 56%, and T c  = 110°C for BZT-BCT–0.08 wt% CeO 2 ceramics. Greatly improved temperature stability of the piezoelectric properties has been observed over a temperature range between 20°C and 90°C. The ferroelectric–paraelectric transition temperature, T c obtained in this study is 17°C higher than those reported earlier.

Description: The oxygen nonstoichiometry of large oxygen-deficient Ruddlesden–Popper oxides La x Sr 3− x Fe 2 O 7−δ (LSFO7- x ) ( x  = 0, 0.25, 0.5) was measured by the high-temperature gravimetry and the coulometric titration. In the composition series, the P (O 2 ) dependencies exhibited typical plateaus at δ = (2−[ ])/2. Meanwhile, La 0.5 Sr 2.5 Fe 2 O 7−δ showed the smallest oxygen nonstoichiometry and was the most thermochemically stable compound against P (O 2 ), temperature, and the La content. Based on the defect equilibrium model and the statistical thermodynamic calculation derived oxygen nonstoichiometric data, the substitution of La for Sr-site can promote the forward reaction of oxygen incorporation, the backward reaction of the disproportionation of the charge carriers, and oxygen redistribution between the O1 and O3 sites, resulting in the reduction of oxygen-deficient and the lower decomposition P (O 2 ). The obtained thermodynamic quantities of the partial molar enthalpy of oxygen, , and the partial molar entropy of oxygen, , calculated from the statistical thermodynamic calculation are in good agreement with those using the Gibbs–Helmholtz equation.

Description: Microstress in reaction-bonded silicon carbide (RBSiC) has been measured using piezo-Raman spectroscopy. Compressive microstresses as high as 2 GPa exist in the silicon phase and tensile microstresses as high as 2.3 GPa exist in the SiC phase of RBSiC. This is much larger than expected for thermoelastic microstress from coefficient of thermal expansion mismatch would provide. Instead the microstresses arise from the crystallization of liquid silicon. During the reaction bonding process, not all of the silicon reacts to form SiC and there is liquid free silicon. The phase transformation of the free silicon from liquid to solid has a large volume expansion, which results in large residual microstress within the silicon and SiC phases of RBSiC.

Description: The single crystal solid-state conversion of fluorapatite-type Sr 5 (PO 4 ) 3 F (Sr-FAP) has been achieved by spark plasma sintering with the assistance of NaF additive. NaF was determined to act as both a sintering aid and impurity solute along the grain boundaries (GBs), controlling both the space charge and GB migration rate. Postsintering isothermal annealing was performed to examine the effect of DC electric field on grain growth. From the space charge potential determined from impedance spectra measurements, in combination with the theoretical contribution of space charge to grain-boundary energy reduction, it was concluded that the magnitude of the space charge in Sr-FAP is temperature dependent. As such, a moderate decrease in polycrystalline GB driving force is the main cause for the increased single crystal migration length that was observed in this study.

Description: Decreasing pitch size in electronic packaging has resulted in a drastic decrease in solder volumes. The Sn grain crystallography and fraction of intermetallic compounds (IMCs) in small-scale solder joints evolve much differently at the smaller length scales. A cross-sectional study limits the morphological analysis of microstructural features to two dimensions. This study utilizes serial sectioning technique in conjunction with electron backscatter diffraction to investigate the crystallographic orientation of both Sn grains and Cu 6 Sn 5 IMCs in Cu/Pure Sn/Cu solder joints in three dimensional (3D). Quantification of grain aspect ratio is affected by local cooling rate differences within the solder volume. Backscatter electron imaging and focused ion beam serial sectioning enabled the visualization of morphology of both nanosized Cu 6 Sn 5 IMCs and the hollow hexagonal morphology type Cu 6 Sn 5 IMCs in 3D. Quantification and visualization of microstructural features in 3D thus enable us to better understand the microstructure and deformation mechanics within these small scale solder joints.

Description: Phase relationships of the CaO–ZnO system in equilibrium with air ( = 0.21 atm) have been studied for the first time using the equilibration/quenching/EPMA technique in the temperature range from 1000°C to 1600°C. In this study, the mutual solubility boundaries of the CaO and ZnO phases have been determined. Both CaO and ZnO have obvious solubilities in each other. The maximum solubility of ZnO in solid CaO phase is 23.21 at.% at 1535°C, and ZnO solid phase can take up to 4.81 at.% CaO at 1535°C. The eutectic point and parts of the liquidus lines have also been determined. The eutectic point was found to be at 1535°C ± 2°C and 0.6612 mole fraction of ZnO. No compound was found in this system, and there were two primary phases: halite-structured CaO (lime) and wurtzite-structured ZnO (zincite). Results from this study were compared with the CaO–ZnO phase diagram calculated by MTDATA 5.10 and its MTOX 8.1 database. The difference was significant, and the thermodynamic description of the system requires a reassessment.

Description: This work investigated the effect of MnO 2 addition on the phase structure, microstructure, and electrical properties of AgSbO 3 -modified (Li,K,Na)(Nb,Ta)O 3 (abbreviated as LKNNT-AS) lead-free piezoelectric ceramics with an optimized composition endowed with a state of two-phase coexistence. A small amount (0.1 wt%) of MnO 2 can significantly further enhance the piezoelectric property of LKNNT-AS ceramics, whose piezoelectric constant d 33 and converse piezoelectric coefficient d 33 * as well as planar electromechanical coupling factor k p reach 363 pC/N, 543 pm/V, and 0.49, respectively. The temperature stability of piezoelectricity in MnO 2 -modified LKNNT-AS samples also improved, which is associated with the more uniform and better thermally stable ferroelectric domains that were revealed by piezoresponse force microscopy.

Description: Free-standing NiCo 2 O 4 @Ni cathodes for aprotic lithium-oxygen batteries were synthesized through a simple hydrothermal process followed by heat treatment in the air. The morphology of the NiCo 2 O 4 deposit changed from nanosheet to nanowire with the increase of hydrothermal time. Further observation revealed that the nanosheet/nanowire NiCo 2 O 4 were assembled by nanoparticles with a size of 10–20 nm. The directional assembly of the nanoparticles were not affected by the reaction time. The influence of catalyst microstructure on the electrochemical performance of Li-O 2 batteries was studied. The results of battery tests in pure oxygen indicate that the cathode material with a high specific surface area, large pore volume and broad pore size distribution can facilitate the discharge reaction, leading to an improved cell performance. As a result, the cathode based on the NiCo 2 O 4 nanowire array delivered a specific discharge capacity of 1682 mAh g −1 at 30 mA g −1 and a stable cyclability of 50 cycles with a capacity limitation of 500 mAh g −1 .

Description: Crystalline pure NaTi 2 (PO 4 ) 3 (NTP) powder was synthesized at 700°C using a simple and low energy, hybrid inorganic–organic, steric entrapment method. Sodium nitrite (NaNO 2 ) and ammonium phosphate dibasic ((NH 4 ) 2 HPO 4 ) dissolved in water, whereas titanium (IV) isopropoxide (Ti[OCH(CH 3 ) 2 ] 4 ) hydrolyzed in water. Ethylene glycol (HOCH 2 CH 2 OH) was used as a polymeric entrapper and hydrolysis of the Ti source was hindered by its dissolution in isopropyl alcohol. The resulting NTP powder was characterized by thermogravimetric analysis/differential thermal analysis, X-ray diffractometry, scanning electron microscopy, specific surface area by Brunauer–Emmett–Teller nitrogen absorption, and particle size analysis. Furthermore, C, H, N were measured by the classical Pregl-Dumas method. The thermal expansion behavior in all { hkl } pole directions was also determined by in situ high-temperature X-ray diffraction using synchrotron radiation and was found to be in agreement with other published studies.

Description: The room temperature mechanical behavior of the fully bainitic steel grade 20CrMoVTiB410 was studied in the as-quenched and tempered conditions. The hardenability response of the steel during heat treatment was assessed. In the as-quenched condition itself, the steel exhibited a good combination of strength, ductility and toughness. Tempering the quenched steel till to 550°C, showed uniform mechanical properties. Tempering at 650°C showed secondary hardening behaviour, where the highest strength and least impact toughness was observed. Tempering at 700°C showed a sharp decrease in strength but with significant enhancement of toughness. The properties obtained were correlated with the microstructure and phase analysis was established using optical, scanning electron microscope, transmission electron microscope and x-ray diffraction techniques.

Description: In present study, 6061- and A356-based nano-composites are fabricated by using the ultrasonic stirring technology (UST) in a coreless induction furnace. SiC nanoparticles are used as the reinforcement. Nanoparticles are added into the molten metal and then dispersed by ultrasonic cavitation and acoustic streaming assisted by electromagnetic stirring. The applied UST parameters in the current experiments are used to validate a recently developed magneto-hydro-dynamics (MHD) model, which is capable of modeling the cavitation and nanoparticle dispersion during UST processing. The MHD model accounts for turbulent fluid flow, heat transfer and solidification, and electromagnetic field, as well as the complex interaction between the nanoparticles and both the molten and solidified alloys by using ANSYS Maxwell and ANSYS Fluent. Molecular dynamics (MD) simulations are conducted to analyze the complex interactions between the nanoparticle and the liquid/solid interface. The current modeling results demonstrate that a strong flow can disperse the nanoparticles relatively well during molten metal and solidification processes. MD simulation results prove that ultrafine particles (10 nm) will be engulfed by the solidification front instead of being pushed, which is beneficial for nano-dispersion.

Description: In this article, the wrinkling behavior and thickness distribution of 5A06 aluminum alloy sheets in an annealed state with thickness of 1.0 mm and 2.5 mm was numerically and experimentally investigated under different hydraulic pressures in the hydroforming of single-layer and double-layer sheets. Note that, in double-layer sheets hydroforming, an upper-aided sheet is needed. The upper, thicker sheet synchronously deforms with the lower, thinner sheet during hydroforming. When the double-layer sheets are separated, a thinner curved sheet part will be manufactured. As can be seen from the simulation and experimental results, the upper, thicker sheet could effectively suppress the wrinkles of the lower, thinner sheet and improve the thickness distribution due to the increasing anti-wrinkle ability of the formed sheet and the interfacial friction between the double-layer sheets. In addition, the maximum hydraulic pressure can be decreased via hydroforming of double-layer sheets; this approach reduces the drawing force for large sheet parts and meets the requirement of energy conservation.

Description: Manual attribution of crystallographic phases from high-throughput x-ray diffraction studies is an arduous task, and represents a rate-limiting step in high-throughput exploration of new materials. Here, we demonstrate a semi-supervised machine learning technique, SS-AutoPhase, which uses a two-step approach to identify automatically phases from diffraction data. First, clustering analysis is used to select a representative subset of samples automatically for human analysis. Second, an AdaBoost classifier uses the labeled samples to identify the presence of the different phases in diffraction data. SS-AutoPhase was used to identify the metallographic phases in 278 diffraction patterns from a FeGaPd composition spread sample. The accuracy of SS-AutoPhase was 〉82.6% for all phases when 15% of the diffraction patterns were used for training. The SS-AutoPhase predicted phase diagram showed excellent agreement with human expert analysis. Furthermore it was able to determine and identify correctly a previously unreported phase.

Description: The present work focuses on the processing of cathode active material of spent lithium ion batteries to improve the recovery of constituent metals using reducing agents. Reductants enhance the solubility of metals, which hitherto have been solubilised to a lesser extent using only acid as leaching agent. Thus, we have investigated sulfuric acid leaching in the presence of sodium bisulfite comparing its efficiency with hydrogen peroxide. By simple acid leaching using 1 M H 2 SO 4 at 368 K and 50 g/L pulp density, 93.4% Li, 66.2% Co, 96.3% Ni and 50.2% Mn were recovered in 240 min. In the presence of 5% H 2 O 2 as a reducing agent at 368 K with 1 M H 2 SO 4 and 50 g/L pulp density, the leaching of cobalt (79.2%) and manganese (84.6%) were significantly improved in 240 min. With the addition of 0.075 M NaHSO 3 as a reducing agent, ~96.7% Li, 91.6% Co, 96.4% Ni and 87.9% Mn were recovered under similar conditions. Sodium bisulfite addition results in better recovery of cobalt and manganese by reducing them to their lower oxidation states. The HSC evaluation of thermodynamic feasibility vis-à-vis x-ray diffraction and scanning electron microscopy characterization of residues generated by leaching with hydrogen peroxide and sodium bisulfite substantiates the governing mechanism.

Description: This paper investigated the non-isothermal crystallization kinetics of the spinel crystals in vanadium slags containing high CaO content. Experiments were performed in combination with theoretical calculation to address this issue, and statistical analyses based on the Crystal Size Distribution theory. The results indicate that low cooling rate and high CaO content benefit the growth of spinel crystals. The growth mechanism is revealed to be controlled by interface reactions and diffusion at the cooling rates of 5 K/min and 15 K/min, respectively. However, at higher temperatures (〉1673 K), the growth of spinel crystals is controlled by nucleation. While the temperature is decreased to 1523 K at the cooling rate of 5 K/min, the mean diameter of spinel crystals could reach 36.44 μm. Experimental results combining with theoretical reveal that low cooling rate benefits spinels growth, especially for the interval of 1523 K–1200 K.

Description: As highly integrated circuits are demanded for high-performance electric devices, small sizes of barium titanate (BaTiO 3 ) as a dielectric material are desirable for the application of multilayer ceramic capacitors. Since the small sizes of the particles degrade the dielectric property, especially below a certain critical size, understanding the probable cause is significant for the high-performance capacitors. Here, we have demonstrated nanosized BaTiO 3 with average size below 30 nm and a uniform size distribution. High-resolution transmission electron microscopy (TEM) shows that the as-synthesized BaTiO 3 contains intragranular pores. We have analyzed the correlation between the intragranular pores inside nanoparticles and their phase ratio of cubic and tetragonal. We have found that the presence of the intragranular pores affects low tetragonality of BaTiO 3 particles, and the intragranular pores are generated by the accumulation of hydroxyl groups during hydrothermal reaction. Formation and accumulation of intragranular pores have been investigated by ex-situ synchrotron X-ray diffraction and TEM analysis, suggesting the phase evolution model of nanosized BaTiO 3 .

Description: To maximize the recovery of iron and copper from copper slag, the modification process by adding a compound additive (a mixture of hematite, pyrite and manganous oxide) and optimizing the cooling of the slag was studied. The phase reconstruction mechanism of the slag modification process was revealed by thermodynamic calculations, x-ray diffraction, optical microscopy and scanning electron microscopy. The results show that the synergy between the burnt lime and the compound additive promotes the generation of target minerals, such as magnetite and copper matte. In addition, the multifunctional compound additive is able to improve the fluidity of the molten slag, which facilitates the coalescence and growth of fine particles of the target minerals. As a result, the percentage of iron distributed in the form of magnetite increased from 32.9% to 65.1%, and that of the copper exiting in the form of metallic copper and copper sulfide simultaneously increased from 80.0% to 90.3%. Meanwhile, the grains of the target minerals in the modified slag grew markedly to a mean size of over 50 μm after slow cooling. Ultimately, the beneficiation efficiency of copper and iron was improved because of the ease with which the target minerals could be liberated.

Description: The high cost and time typically expended in the successful deployment of new materials into high-performance commercial products is attributable to multiple factors. The most significant of these include the heavy reliance on experiments, the persisting disconnect between multiscale experiments and multiscale models, the lack of a broadly accessible data and knowledge infrastructure that can support the implementation of a holistic systems approach, and the lack of a suitable framework for facilitating and enhancing the critically needed cross-disciplinary collaborations. The emerging discipline of materials data science and informatics (MDSI) promises to address these key technology gaps. The potential benefits to the materials innovation enterprise that could accrue from an aggressive adoption of the novel concepts and toolsets offered by MDSI are examined. A specific vision is expounded for the role of MDSI in bridging the large gap that exists between the multiscale materials experiments and the multiscale materials models.

Description: Greenhouse gas (GHG) generation is inherent in the production of aluminium by a technology that uses carbon anodes. Most of those GHG are composed of CO 2 produced by redox reaction that occurs in the cell. However, a significant fraction of the annual GHG production is composed of perfluorocarbons (PFC) resulting from anode effects (AE). Multiple investigations have shown that tetrafluoromethane (CF 4 ) can be generated under low-voltage conditions in the electrolysis cells, without global anode effect. The aim of this paper is to find a quantitative relationship between monitored cell parameters and the emissions of CF 4 . To achieve this goal, a predictive algorithm has been developed using seven cell indicators. These indicators are based on the cell voltage, the noise level and other parameters calculated from individual anode current monitoring. The predictive algorithm is structured into three different steps. The first two steps give qualitative information while the third one quantitatively describes the expected CF 4 concentration at the duct end of the electrolysis cells. Validations after each step are presented and discussed. Finally, a sensitivity analysis was performed to understand the effect of each indicator on the onset of low-voltage PFC emissions. The standard deviation of individual anode currents was found to be the dominant variable. Cell voltage, noise level, and maximum individual anode current also showed a significant correlation with the presence of CF 4 in the output gas of an electrolysis cell.

Description: The study of material failure with digital analytics is in its infancy and offers a new perspective to advance our understanding of damage initiation and evolution in metals. In this article, we study the failure of aluminum using data-enabled methods, statistics and data mining. Through the use of tension tests, we establish a multivariate acoustic-data matrix of random damage events, which typically are not visible and are very difficult to measure due to their variability, diversity and interactivity during damage processes. Aluminium alloy 6061-T651 and single crystal aluminium with a (111) orientation were evaluated by comparing the collection of acoustic signals from damage events caused primarily by slip in the single crystal and multimode fracture of the alloy. We found the resulting acoustic damage-event data to be large semi-structured volumes of Big Data with the potential to be mined for information that describes the materials damage state under strain. Our data-enabled analyses has allowed us to determine statistical distributions of multiscale random damage that provide a means to quantify the material damage state.

Description: A two-stage sequential heavy reduction (HR) method, in which the reduction amount was increased both before and after the solidification end, is presented to simultaneously improve the homogeneity and compactness of the continuous casting bloom. With bearing steel GCr15 chosen as the specific research steel, a three-dimensional thermal–mechanical finite element model was developed to simulate and analyze the thermal and mechanical behaviors of the continuous casting bloom during the HR process. In order to ensure the accuracy of the simulation, the constitutive model parameters were derived from the experimental results. The predicted temperature distribution and shell thickness were verified using a thermal infrared camera and nail shooting results, respectively. The real measured relationship between the HR pressure and amount were applied to verify the mechanical model. The explorative application results showed that the quality of the bloom center and compactness of rolled bars have both been significantly improved after the HR was applied.

Description: The mass of automotive components has a direct influence on several aspects of vehicle performance, including both fuel consumption and tailpipe emissions, but the real environmental benefit has to be evaluated considering the entire life of the products with a proper life cycle assessment. In this context, the present paper analyzes the environmental burden connected to the production of a safety-relevant aluminum high-pressure die-casting component for commercial vehicles (a suspension cross-beam) considering all the phases connected to its manufacture. The focus on aluminum high-pressure die casting reflects the current trend of the industry and its high energy consumption. This work shows a new method that deeply analyzes every single step of the component’s production through the implementation of a wide database of primary data collected thanks to collaborations of some automotive supplier companies. This energy analysis shows significant environmental benefits of aluminum recycling.

Description: In this study, we prepared an aqueous dispersion of fluorine-doped hydroxyapatite (FHA) nanoparticles by a wet chemical method. For the first time, the as-prepared aqueous dispersion of FHA nanoparticles was directly used as suspension for depositing nanostructured FHA coating on stainless steel substrate by suspension plasma spray (SPS) method. Field-emission scanning electron microscopy images confirm that the coating was nanostructured. X-ray Diffraction pattern, Fourier-transform infrared spectroscopy, and Raman spectra show that the as-sprayed coating was FHA phases. The experimental result confirmed that OH − and F − ions have been well kept in FHA crystal lattice and structural integrity has been maintained during SPS process by using an aqueous dispersion of FHA nanoparticles. The potentiodynamic polarization and electrochemical impedance spectroscopy results prove that the nanostructured FHA coating can greatly enhance the anticorrosion performance of stainless steel in phosphate-buffered saline solution.

Description: We report a novel joint fabrication method for YBa 2 Cu 3 O 7− x (Y123) bulk superconductors without pressure loading, based on a well-controlled high-temperature process. Due to the direction of the heat fluxes in a box furnace, the surfaces of the joined samples melt first, and the crystal morphology of the original YBa 2 Cu 3 O 7− x bulks remains. After the joining process, part of the texture zone is used as a seed to grow new texture crystals for nucleation during cooling. Finally, a high-quality artificial grain boundary forms without acting as a weak link, which is supported by the trapped field distribution. Details of the joint are presented, including its microstructure and micro-orientation. Moreover, the trapped field values at 65 and 45 K are presented.

Description: A comparison between 2D and 3D Finite Element Method based simulations on the tunability properties of ferroelectric – linear dielectric composites is presented. Dependences of the effective permittivity and tunability on the concentration of the linear phases are presented and it is shown that there are important differences between the two approaches. The appropriateness of such simulations in describing realistic composite systems is discussed, too.

Description: A novel molten-salt and microwave coassisted carbothermal reduction (termed as MSM-CTR) method was developed to prepare ZrB 2 powders from raw materials of ZrO 2 , B 4 C, and amorphous carbon. The results indicated that the carbothermal reduction reaction for synthesizing ZrB 2 was initiated at the temperature as low as 1150°C, and phase pure ZrB 2 powders were obtained after only 20 min at 1200°C, which were significantly milder than that of the conventional CTR method as well as the modified CTR method even using active metal as additional reducing agents. More interestingly, the as-obtained ZrB 2 powders consisted of well-defined single-crystalline nanorods, which had diameters of 40–80 nm and high aspect ratios of 〉10. These results demonstrated that the MSM-CTR is a simple and efficient route for preparation of high-quality ZrB 2 powders.

Description: Nearly 400 million years of evolution and field-testing by the natural world has given humans thousands of wood types, each with unique structure–property relationships to study, exploit, and ideally, to manipulate, but the slow growth of trees makes them a recalcitrant experimental system. Variations in wood features of two genotypes of peach ( Prunus persica L.) trees, wild-type and crinkle-leaf, were examined to elucidate the nature of weak wood in crinkle-leaf trees. Crinkle-leaf is a naturally-occurring mutation in which wood strength is altered in conjunction with an easily observed ‘crinkling’ of the leaves’ surface. Trees from three vigor classes (low growth rate, average growth rate, and high growth rate) of each genotype were sampled. No meaningful tendency of dissimilarities among the different vigor classes was found, nor any pattern in features in a genotype-by-vigor analysis. Wild-type trees exhibited longer vessels and fibers, wider rays, and slightly higher specific gravity. Neither cell wall mechanical properties measured with nanoindentation nor cell wall histochemical properties were statistically or observably different between crinkle-leaf and wild-type wood. The crinkle-leaf mutant has the potential to be a useful model system for wood properties investigation and manipulation if it can serve as a field-observable vegetative marker for altered wood properties.

Description: As the size of databases has significantly increased, whether through high throughput computation or through informatics-based modeling, the challenge of selecting the optimal material for specific design requirements has also arisen. Given the multiple, and often conflicting, design requirements, this selection process is not as trivial as sorting the database for a given property value. We suggest that the materials selection process should minimize selector bias, as well as take data uncertainty into account. For this reason, we discuss and apply decision theory for identifying chemical additions to Ni-base alloys. We demonstrate and compare results for both a computational array of chemistries and standard commercial superalloys. We demonstrate how we can use decision theory to select the best chemical additions for enhancing both property and processing, which would not otherwise be easily identifiable. This work is one of the first examples of introducing the mathematical framework of set theory and decision analysis into the domain of the materials selection process.

Description: Oxide glasses exhibit slow crack growth under stress intensities below the fracture toughness in the presence of water vapor or liquid water. The log of crack velocity decreases linearly with decreasing stress intensity factor in Region I. For some glasses, at a lower stress intensity, K o , log v asymptotically diminishes where there is no measurable crack growth. The same glasses exhibit static fatigue, or a decreasing strength for increasing static loading times, as cracks grow and stress intensity eventually reaches the fracture toughness. In this case, some glasses exhibit a low stress below which no fatigue/failure is observed. The absence of slow crack growth under a low stress intensity factor is called the fatigue limit. Currently, no satisfactory explanation exists for the origin of the fatigue limit. We show that the surface stress relaxation mechanism, which is promoted by molecular water diffusion near the glass surface, may be the origin of the fatigue limit. First, we hypothesize that the slowing down of slow crack growth takes place due to surface stress relaxation during slow crack growth near the static fatigue limit. The applied stress intensity becomes diminished by a shielding stress intensity due to relaxation of crack tip stresses, thus resulting in a reduced crack velocity. This diminishing stress intensity factor should result in a crack growth rate near the static fatigue limit that decreases in time. By performing Double Cantilever Beam crack growth measurements of a soda-lime silicate glass, a decreasing crack growth rate was measured. These experimental observations indicate that surface stress relaxation is causing crack velocities to asymptotically become immeasurably small at the static fatigue limit. Since the surface stress relaxation was shown to take place for various oxide glasses, the mechanism for fatigue limit explained here should be applicable to various oxide glasses.

Description: Al-4.5wt.%Cu-5wt.%TiB 2 in situ composite, fabricated by stir casting through a mixed salt reaction route process, needs further processing to exclude casting defects. Mushy state rolling has been developed as an easy and energy-efficient method for microstructural refinement and improvement in mechanical properties. It has been carried out at 621°C and 632°C with 20 vol.% and 30 vol.% of liquid, respectively, for up to 5% reduction in thickness. Mushy state rolling of the as-cast composite gives rise to a bimodal microstructure, which consists of very fine equiaxed grains adjacent to the rolled surface and comparatively larger elongated grains away from the rolled surface of the sample. Microhardness of the mushy state rolled sample has been observed to decrease gradually from edge to center of the rolled sample. The presence of the dislocation tangles and subgrains formed by dynamic recovery within solid-state deformed elongated grains and formation of recrystallized grains just adjacent to the second-phase particles have been examined with the help of electron backscattered diffraction and transmission electron microscopy analysis.

Description: The effect of anisotropic hardening models on springback of an S-rail part was investigated. Two advanced constitutive models based on distortional and kinematic hardening, which captured the Bauschinger effect, transient hardening, and permanent softening during strain path change, were implemented in a finite element (FE) code. In-plane compression–tension tests were performed to identify the model parameters. The springback of the S-rail after forming a 980 MPa dual-phase steel sheet sample was measured and analyzed using different hardening models. The comparison between experimental and FE results demonstrated that the advanced anisotropic hardening models, which are particularly suitable for non-proportional loading, significantly improved the springback prediction capability of an advanced high strength steel.

Description: A recent Critical Materials Strategy report highlighted the supply chain risk associated with neodymium and dysprosium, which are used in the manufacturing of neodymium-iron-boron permanent magnets (PM). In response, the Critical Materials Institute is developing innovative strategies to increase and diversify primary production, develop substitutes, reduce material intensity and recycle critical materials. Our goal in this paper is to propose an economic model to quantify the impact of one of these strategies, material intensity reduction. Technologies that reduce material intensity impact the economics of magnet manufacturing in multiple ways because of: (1) the lower quantity of critical material required per unit PM, (2) more efficient use of limited supply, and (3) the potential impact on manufacturing cost. However, the net benefit of these technologies to a magnet manufacturer is an outcome of an internal production decision subject to market demand characteristics, availability and resource constraints. Our contribution in this paper shows how a manufacturer’s production economics moves from a region of being supply-constrained, to a region enabling the market optimal production quantity, to a region being constrained by resources other than critical materials, as the critical material intensity changes. Key insights for engineers and material scientists are: (1) material intensity reduction can have a significant market impact, (2) benefits to manufacturers are non-linear in the material intensity reduction, (3) there exists a threshold value for material intensity reduction that can be calculated for any target PM application, and (4) there is value for new intellectual property (IP) when existing manufacturing technology is IP-protected.

Description: As the demand for personal electronic devices, wind turbines, and electric vehicles increases, the world becomes more dependent on rare earth elements. Given the volatile, Chinese-concentrated supply chain, global attempts have been made to diversify supply of these materials. However, the overall effect of supply diversification on the entire supply chain, including increasing low-value rare earth demand, is not fully understood. This paper is the first attempt to shed some light on China’s supply chain from both demand and supply perspectives, taking into account different Chinese policies such as mining quotas, separation quotas, export quotas, and resource taxes. We constructed a simulation model using Powersim Studio that analyzes production (both legal and illegal), production costs, Chinese and rest-of-world demand, and market dynamics. We also simulated new demand of an automotive aluminum-cerium alloy in the US market starting from 2018. Results showed that market share of the illegal sector has grown since 2007–2015, ranging between 22% and 25% of China’s rare earth supply, translating into 59–65% illegal heavy rare earths and 14–16% illegal light rare earths. There will be a shortage in certain light and heavy rare earths given three production quota scenarios and constant demand growth rate from 2015 to 2030. The new simulated Ce demand would require supply beyond that produced in China. Finally, we illustrate revenue streams for different ore compositions in China in 2015.

Description: Strontium barium niobate (SBN) is a tungsten bronze family ferroelectric which shows promising thermoelectric properties under reducing conditions. It is found here that the enhanced electrical conductivity of oxygen-deficient SBN correlates with the formation of a NbO 2 secondary phase. The effects of the reducing environment and the NbO 2 phase formation are studied via a detailed defect chemistry analysis. Increasing amounts of the NbO 2 phase are accompanied by an interesting mechanism where the A-site occupancy of the SBN matrix increases. The resulting donor defects source the large carrier concentrations which cause the enhanced electrical conductivity necessary for thermoelectric performance. In investigation of the phase equilibria, it is found that a solid solution between (Sr 0.6 ,Ba 0.4 )Nb 2 O 6 and (Sr 0.6 ,Ba 0.4 ) 1.2 Nb 2 O 6 exists and that the A-site filling is found to occur at more modest reduction conditions in Sr- and Ba-rich compositions. Finally, thermogravimetric analysis of the reoxidation process is performed, and the results suggest that the A-site filling is compensated ionically. Not only do the presented results explain the enhanced electrical conductivity of oxygen-deficient strontium barium niobate but also modification of the site occupancies by reduction and reoxidation may widen the design space for property modification in tungsten bronze-structured materials in general.

Description: This study evaluates the change of flow stress as related to dislocation density in SrTiO 3 single crystals in order to provide guidance for later electrical studies. The key parameters varied are temperature and loading rate during the deformation. It is found that in 〈100〉-oriented SrTiO 3 single crystals, the dislocation density is enhanced by plastic deformation, more so at higher temperature as compared to room temperature. The experimental approach of quantifying the dislocation density through a determination of ex situ X-ray diffraction rocking curves was successfully applied over the upper temperatures region of the lower temperature ductility zone for strontium titanate, i.e., in the so-called “A-regime”. For 1.0% deformed samples deformed at 300°C, a fourfold increase in dislocation density to 1.4 × 10 13  m −1 was found as compared to the nondeformed state (3.7 × 10 12  m −1 ). Cross-section techniques confirmed that the observed dislocation densities measured at the surfaces were identical to those seen in the core of the crystals. The use of rapid changes in loading rate provided an estimate for activation volume of the dislocation core for both 25°C and 300°C.

Description: To understand the potential for use of the Hf–Al–C ternary compounds, (HfC) n Al 3 C 2 (Hf 2 Al 3 C 4 and Hf 3 Al 3 C 5 ) and (HfC) n Al 4 C 3 (Hf 2 Al 4 C 5 and Hf 3 Al 4 C 6 ) were investigated using density functional theory, including crystal structure, electronic structure, compressibility, and elastic properties. The theoretical density of (HfC) n Al 3 C 2 (4.10–4.16 g/cm 3 ) is higher than that of (HfC) n Al 4 C 3 (3.92–3.98 g/cm 3 ), due to the smaller number of lighter Al–C layers. With increasing numbers of Hf–C layers, the Hf–C and Al–C bond lengths remain almost unchanged. In none of the compounds is there a gap around the Fermi energy ( E f ), which implies they are metal-like conductors. With increasing pressure, there is greater shrinkage along the c axis than the a axis. The bond stiffness increases with increasing pressure. In general, (HfC) n Al 3 C 2 has higher elastic stiffness than (HfC) n Al 4 C 3 , with the moduli increasing with the number of Hf–C layers. The Hf–Al–C compounds as well as the brittle Zr–Al–C compounds all have low shear moduli/bulk moduli ratio ( G / B ) from 0.71 to 0.78, suggesting that the G / B ratio is not always a suitable measure of ductility.

Description: Inorganic coatings are being developed to protect marble monuments and sculpture from weathering. In this work, the acid resistance of hydroxyapatite (HAP), calcium oxalate, and calcium tartrate coatings on Carrara marble were compared. To quantify the rate of attack on calcite, the pH of the solution was measured. This approach was validated by confirming that the rate of dissolution of untreated calcite inferred from the change in pH agrees with data in the literature. Calcium tartrate coatings were incomplete, and the mineral is so soluble that it offered no significant protection. Calcium oxalate forms coherent coatings, so it serves as a sacrificial coating in spite of having solubility comparable to that of calcite. HAP was deposited from aqueous solutions of 1 M diammonium hydrogen phosphate (DAP), with or without millimolar additions of CaCl 2 (which improved coverage) and (NH 4 ) 2 CO 3 (which resulted in cracking). The best HAP coatings remained porous; nevertheless, they were comparable to oxalate coatings in the short term and superior in the long term, reducing the dissolution rate by about 40%.

Description: Single-phase, c -axis-oriented BiCuSeO thin films have been directly grown on the commercial silicon (001) wafers without any surface pretreatment by using pulsed laser deposition. X-ray diffraction pole figure confirms that the film does not have any ab- plane texture, whereas cross-sectional transmission electron microscopy shows good crystallinity of the film even if there exists an amorphous native oxide layer on the wafers surface. At room temperature, the resistivity of the film is about 14 mΩ cm, which is much lower than that reported for corresponding single crystals as well as polycrystalline bulks. This work demonstrates the possibility of using the available state-of-the-art silicon processing techniques to create BiCuSeO-based thin-film thermoelectric devices.

Description: An approach to improve the lifetime of air plasma sprayed (APS) thermal barrier coatings (TBCs) by modifying the interfacial microstructure has been reported. The laser powder deposition technique was employed to fabricate the mesh structure (with the same composition as the bond coat) at the ceramic–substrate interface. After thermal cycling test, the APS TBCs with the mesh exhibited a much less spallation degree (5%–10%) compared with the reference samples without mesh (〉50%), implying that the mesh is effective in impeding the crack propagation along the interface. In addition, the effect of the mesh geometry parameters, e.g., height and spacing of mesh, on the spallation degree of TBCs was also investigated. Based on the results of experiment and calculation, the optimal mesh parameters were proposed.

Description: (Cr 2 Ti)AlC 2 is a newly discovered MAX phase with ordered occupations of Ti and Cr atoms on M sites. The Cr-containing MAX phase is expected showing magnetic property, which provides functional applications in spintronics and as self-monitoring smart coating. The magnetic states of (Cr 2 Ti)AlC 2 are predicted by GGA and GGA +  U methods and compared to those of Cr 2 AlC. The ground states are predicted as FM or AFM-XX configurations depending on the calculation methods. Analysis of the electronic structure shows that the magnetic moments mainly originate from the net spins of Cr 3 d valence electrons, whereas the contribution of other atoms is negligible. The calculated magnetic moments of Cr atoms in (Cr 2 Ti)AlC 2 are higher than those in Cr 2 AlC due to the larger distance between the out-plane Cr atoms separated by the intercalated nonmagnetic Ti–C slab. This work provides an insight on tailoring magnetic properties of MAX phases by modifying the crystal structure.

Description: A two-step solid-state reaction is proposed to synthesize monophasic cobalt tellurate Co 3 TeO 6 (CTO), a type II multiferroic, using Co 3 O 4 and TeO 2 as the starting reagents. First step of the reaction results in the secondary monoclinic ( P 2 1 / c ) CoTeO 4 compound, which on further calcination (second step) leads to the primary monoclinic ( C 2/ c ) Co 3 TeO 6 phase. High-resolution synchrotron X-ray diffraction and the subsequent Rietveld analysis are used to probe different phases present in the synthesized CTO and to achieve its single phase. X-ray absorption near-edge structure studies at Co K and Te L edges reveal mixed oxidation states (Co 2+/3+ ) of Co and hexavalent Te, respectively. Charge imbalance due to mixed valence Co ions has been attributed to cations vacancies. Enhanced multiferroic properties, such as effective magnetic moment, spin phonon coupling, etc., have been attributed to the aforementioned observations in grown ceramic CTO via proposed synthesis route.

Description: Low-temperature conductivity mechanisms were identified in acceptor-doped SrTiO 3 single crystals quenched from high temperatures under reducing conditions. Impedance spectroscopy measurements made on samples of the prototypical perovskite structure doped with iron provided a framework for creating a complete conductivity model for a well-defined point defect system. The dominant conductivity mechanism in the room-temperature range was identified as being controlled by oxygen vacancy hopping. The activation energy for oxygen vacancy migration, an often debated value in the perovskite community, is determined to lie within the range of 0.59–0.78 eV for the iron-doped system with the bottom of this range approaching the intrinsic value for oxygen vacancy hopping in an undoped single crystal. At low temperatures, oxygen vacancies form defect complexes with iron impurities, and the observed range of activation energies is explained and modeled in terms of an oxygen vacancy trapping mechanism.

Description: In this study, the influence of the shape of the doctor blade on the flow inside the tape casting unit and on the resulting tape properties is investigated both numerically and experimentally. Using the results from the analysis of the produced tape and from the simulations of the flow inside the tape casting unit, the relationships between blade geometry and the particle orientation in the resulting tape, as well as the resulting tape thickness, are shown. Additionally, the experimentally and numerically obtained results were compared to an analytical model for the prediction of the tape thickness. The simulations were carried out using the particle-based smoothed particle hydrodynamics method using a non-Newtonian fluid model to describe the ceramic slurry. Both in experiment and simulation, the influence of the blade geometry on the resulting tape shows good agreement.

Description: The crystallization mechanisms for Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (LATP) glass ceramics were studied using thermophysical property characterization techniques. Differential scanning calorimetry (DSC) revealed two separate exothermic events that were ascribed to the initial growth and growth to coherency of a dendritic phase. It was found that the commonly used Johnson-Mehl-Avrami is not a suitable kinetic model for this material. Rather, the Sestak-Berggren (SB) autocatalytic kinetic model was used to analyze the DSC data and the activation energy for initial growth (259 kJ/mol) and coherency (272 kJ/mol) was calculated using isoconversional methods. The calculated parameters for the SB model were used to compare experimental and calculated values for heat flow during the crystallization of LATP and good fits were found for both exothermic events.

Description: An environment friendly nonlinear chalcogenide glass fiber with a Ge-Sb-Se core and a Ge-Se cladding is fabricated for bright broadband mid-infrared (MIR) supercontinuum (SC) generation. The fabricated Ge-Sb-Se/Ge-Se fiber with a core diameter of 6 μm shows zero group velocity dispersion at ~4.2 μm and ~7.3 μm. By pumping the fiber with a length of 11 cm at 4.485 μm with 330 fs pulses, we achieve a SC covering the 2.2–12 μm spectral range and with an output average power of ~17 mW. This bright broadband SC source is promising for high-resolution MIR spectroscopy.

Description: Metal films on polymer substrates are commonly used in flexible electronic devices and may be exposed to large deformations during application. For flexible electronics, the main requirement is to remain conductive while stretching and compressing. Therefore, the electro-mechanical behaviour of 200-nm-thick Cu films on polyimide with two different microstructures (as-deposited and annealed) were studied by executing in situ fragmentation experiments with x-ray diffraction, under an atomic force microscope, and with 4-point probe resistance measurements in order to correlate the plastic deformation with the electrical behaviour. The three in situ techniques clearly demonstrate different behaviours controlled by the microstructure. Interestingly, the as-deposited film with a bi-modal microstructure is more suited for flexible electronic applications than an annealed film with homogenous 1- µ m-sized grains. The as-deposited film reaches a higher yield stress, with unchanged electrical conductivity, and does not show extensive surface deformation during straining.

Description: SiC-based composites exhibit oxidative embrittlement at intermediate temperatures. Although the mechanisms of internal oxidation in composites with initially hermetic matrices have been studied extensively, comparable studies on composites with semipermeable matrices, such as those produced by polymer infiltration and pyrolysis, have not been reported. The present article focuses on the latter class of composites, specifically a SiC f /SiCN m with a dual BN/Si 3 N 4 fiber coating. It describes detailed SEM and TEM analyses of the microstructure before and after oxidation in dry air or water vapor at 800°C. The results show that internal oxidation is more aggressive in water vapor and occurs appreciably even in the absence of an applied stress. The sequence of oxidation of the constituent phases appears to be consistent with the underlying thermodynamic hierarchy for the respective oxidation reactions. Notably, contrary to existing models based on preferential oxidation of BN coatings, oxidation occurs first on the SiC fiber surfaces and the Si 3 N 4 overcoat; crystalline BN remains even after significant fiber and matrix oxidation has occurred. The results are discussed in terms of rate-controlling kinetic processes, the effect of oxidant type, and applied stress.

Description: Ultralight Si 3 N 4 ceramic foams have been successfully prepared through particle-stabilized foams method, which is based on the adsorption of in situ hydrophobized Si 3 N 4 particles to the liquid/air interface of the foams. Here, we firstly used a long-chain surfactant cetyltrimethylammonium chloride to render the Si 3 N 4 particles partially hydrophobic. By tailoring the surfactant concentration and pH values of the suspensions, the wet foams were stabilized to avoid coarsening and coalescence. SEM results show that the Si 3 N 4 ceramic foams possess single strut walls with elongated β-Si 3 N 4 grains interlocking with each other, and their pores are uniform with an average pore size of 95 μm. The obtained ceramic foams maintain compressive strength of 1.34 ± 0.13 MPa with porosity of 92.0%, when the suspension contains 3 mmol/L surfactant at the pH of 11.0.

Description: Mullite whiskers frameworks with an ultrahigh porosity were fabricated by the vapor-phase reaction of AlF 3 , Al 2 O 3 , and SiO 2 and adding expandable mesocarbon microbeads (MCMB) as a pore-forming agent. A large volume expansion of 122% for MCMB due to its layered structure occurred during the formation of mullite whiskers, resulting in the expansion of samples and high porosities of 87.7%–98.2% at 50–90 wt% MCMB contents. Perfect whiskers and a lap-joint structure formed due to the formation of mullites through the vapor-phase reaction. A bimodal pore structure was achieved from the spaces of the whiskers framework and burning of the expanded MCMB. High compressive strengths of 1.7 to 5.4 MPa were obtained for the porous mullite at porosities of 94.2%–87.7%, which suggested a rigid structure; these strengths at the ultrahigh porosities are attributed to the merit of the framework with high strength whiskers and their strong bonding.

Description: A specimen having a stoichiometric composition of KSbO 3 ·(KSb) calcined at 800°C has an R rhombohedral structure (RS), and changes to a Pn cubic structure (CS) when calcined at 1100°C. Finally, a 〈111〉-oriented rhombohedral phase is formed in the specimen calcined at 1230°C. K/Sb ratio decreases from 1.0 in RS, 0.93 in CS, and finally to 0.85 in 〈111〉-oriented rhombohedral phases. On the other hand, a specimen having a K-excess composition of K 1.1 SbO 3 calcined at 800°C shows a RS that is maintained in the K-excess specimen calcined at 1230°C. The composition of these specimens is very close to KSb. Therefore, the RS with a space group of R is a stable form of KSbO 3 . The formation of Pn cubic and 〈111〉-oriented R phases can be explained by the evaporation of K 2 O during the calcination process at temperatures above 1100°C.

Description: As the manufacturing time, quality, and cost associated with additive manufacturing (AM) continue to improve, more and more businesses and consumers are adopting this technology. Some of the key benefits of AM include customizing products, localizing production and reducing logistics. Due to these and numerous other benefits, AM is enabling a globally distributed manufacturing process and supply chain spanning multiple parties, and hence raises concerns about the reliability of the manufactured product. In this work, we first present a brief overview of the potential risks that exist in the cyber-physical environment of additive manufacturing. We then evaluate the risks posed by two different classes of modifications to the AM process which are representative of the challenges that are unique to AM. The risks posed are examined through mechanical testing of objects with altered printing orientation and fine internal defects. Finite element analysis and ultrasonic inspection are also used to demonstrate the potential for decreased performance and for evading detection. The results highlight several scenarios, intentional or unintentional, that can affect the product quality and pose security challenges for the additive manufacturing supply chain.

Description: To promote the application of high strength steels in automobile bodies, the practicability of hot hydroforming of tube by resistance heating is illustrated. From the results of experiments conducted to measure temperature distributions of the tube during the forming process, a method to improve temperature uniformity has been proposed and achieved. Validity was evaluated by examining the effects of hot gas forming on the microstructure and hardness. Results indicate an obvious temperature difference along the axial direction for two cross-sectional shapes: the temperature in the middle zone of the tube is higher than that at its ends. Both thermal convection and cross-sectional shape have only a limited effect on the temperature distribution. The main reason for non-uniform temperature distribution is the heat transition between the electrodes and the tube ends. The temperature difference decreased as the heating rate increased. In contrast, the temperature distribution was even along the circumferential direction for both cross-sectional shapes. Adjusting the contact resistance is a useful method of reducing the temperature difference. In this study, the temperature difference was successfully decreased to 20°C, while reaching a maximum temperature of 750°C, which is adequate for both forming and quenching. A rectangular component was formed to validate the practicality and efficiency of tube hot hydroforming by resistance heating. The hardness and microstructure met the requirements of 22MnB5, which demonstrates both the forming efficiency and quantity advantages of hot gas hydroforming by resistance heating.

Description: Graphene has superior mechanical properties, and previous studies have shown that it can be used as a fiber laminate in metal-graphene nanocomposites. Our research outlines the advantages and disadvantages of different Ni-graphene nanocomposite laminates. Using molecular dynamics, Ni-graphene nanocomposites are studied under mode I loading normal to the graphene laminate plane. The stress intensity factor ( \(K_{\text{I}}\) ) is predicted for the nanocomposite at varying distances between a simulated crack and the graphene sheet(s) in the Ni-matrix. We find that \(K_{\text{I}}\) of the Ni-matrix is reduced with the addition of graphene sheet. However, for a single graphene sheet in the Ni-matrix, \(K_{\text{I}}\) increases with increased spacing between the crack and the graphene sheet. This is due to the change in the crack-generated stress field in the region between the Ni-matrix containing the crack and the graphene sheet, which leads to the lower stress values at which dislocation nucleation occurs compared to single-crystal Ni. For multiple layers of graphene sheets in the Ni-matrix, we find that failure occurs exclusively by delamination at a lower stress than the one-layer case. This research concludes that fabricated Ni-graphene nanocomposites can be tuned for optimal fracture strength by the structural arrangement of graphene sheets within the Ni-matrix.

Description: Bog manganese ore, associated with the banded iron formation of the Iron Ore Group (IOG), occurs in large volume in northern Odisha, India. The ore is powdery, fine-grained and soft in nature with varying specific gravity (2.8–3.9 g/cm 3 ) and high thermo-gravimetric loss, It consists of manganese (δ-MnO 2 , manganite, cryptomelane/romanechite with minor pyrolusite) and iron (goethite/limonite and hematite) minerals with sub-ordinate kaolinite and quartz. It shows oolitic/pisolitic to globular morphology nucleating small detritus of quartz, pyrolusite/romanechite and hematite. The ore contains around 23% Mn and 28% Fe with around 7% of combined alumina and silica. Such Mn ore has not found any use because of its sub-grade nature and high iron content, and is hence considered as waste. The ore does not respond to any physical beneficiation techniques because of the combined state of the manganese and iron phases. Attempts have been made to recover manganese and iron value from such ore through smelting. A sample along with an appropriate charge mix when processed through a plasma reactor, produced high-manganese steel alloy having 25% Mn within a very short time (〈10 min). Minor Mn content from the slag was recovered through acid leaching. The aim of this study has been to recover a value-added product from the waste.

Description: Praseodymium nickelate (Pr 2 NiO 4 ) is an active oxygen electrode for solid oxide fuel cells, but undergoes phase transition at elevated temperatures (e.g., 750°C). Quantification of this phase evolution in an operating single cell is challenging because of the overlap of X-ray diffraction (XRD) peaks between the cathode and oxide current collector. In this work, we replace the oxide current collector with a gold metal grid, circumventing these challenges by allowing the exposure of the cathode to the X-ray beam, while eliminating peak overlap. Quantification of the phase evolution was performed by a least-squares fitting of the linear combination of XRD standards against the experimental patterns. Energy-dispersive spectroscopy analysis on long-term operated cells showed the absence of reactions between the gold grids and the cathodes. Additionally, the grids exhibited excellent mechanical stability under operating conditions and enabled similar cell performance as an oxide current collector.

Description: X-ray tomography has provided a non-destructive means for microstructure characterization in three dimensional (3D) and four dimensional (4D) (i.e., structural evolution over time), in which projections of a material’s structure are typically reconstructed using the filtered-back-projection (FBP) method or algebraic reconstruction techniques. The reconstructed images are typically segmented to conduct microstructural quantification. The process can be quite time consuming and computationally intensive. In this paper, we present an overview of our recent work on utilizing a limited (Nyquist under-sampled) number of unique perspective radiographs for computed tomography reconstruction of heterogeneous material (e.g., composites and alloys) structural quantification, property prediction and microstructural reconstruction in 3D and 4D. The proposed approach is significantly more efficient and computationally less intensive than FBP. We first show that an inverse superposition of properly normalized attenuated intensity along different x-ray paths leads to a probability map for the material system, which provides the probability of finding a particular phase at a point in the imaged sample volume. Spatial correlation functions, which are statistical morphological descriptors of the material, are readily computed from the associated probability map. Using effective medium theory and the computed correlation functions, accurate predictions of physical properties (e.g., elastic moduli and thermal/electrical conductivity) can then be obtained. Finally, we present a stochastic reconstruction procedure that generates an accurate rendition of the 3D microstructure from a reduced number of tomographic projections. This stochastic reconstruction method can be easily adapted to reconstruct 4D structural evolution from a small number of in situ projections.

Description: The influence of the electrode immersion depth on the electromagnetic, flow and temperature fields, as well as the solidification progress in an electroslag remelting furnace have been studied by a transient three-dimensional coupled mathematical model. Maxwell’s equations were solved by the electrical potential approach. The Lorentz force and Joule heating were added into the momentum and energy conservation equations as a source term, respectively, and were updated at each time step. The volume of fluid method was invoked to track the motion of the metal droplet and slag–metal interface. The solidification was modeled by an enthalpy–porosity formulation. An experiment was carried out to validate the model. The total amount of Joule heating decreases from 2.13 × 10 5  W to 1.86 × 10 5  W when the electrode immersion depth increases from 0.01 m to 0.03 m. The variation law of the slag temperature is different from that of the Joule heating. The volume average temperature rises from 1856 K to 1880 K when the immersion depth increases from 0.01 m to 0.02 m, and then drops to 1869 K if the immersion depth continuously increases to 0.03 m. As a result, the deepest metal pool, which is around 0.03 m, is formed when the immersion depth is 0.02 m.

Description: Accelerating the pace of materials discovery and development requires new approaches and means of collaborating and sharing information. To address this need, we are developing the Materials Commons, a collaboration platform and information repository for use by the structural materials community. The Materials Commons has been designed to be a continuous, seamless part of the scientific workflow process. Researchers upload the results of experiments and computations as they are performed, automatically where possible, along with the provenance information describing the experimental and computational processes. The Materials Commons website provides an easy-to-use interface for uploading and downloading data and data provenance, as well as for searching and sharing data. This paper provides an overview of the Materials Commons. Concepts are also outlined for integrating the Materials Commons with the broader Materials Information Infrastructure that is evolving to support the Materials Genome Initiative.

Description: To lower the smelting temperature associated with the carbothermic reduction processing of laterite, the optimization of slag and alloy systems was investigated to enable the reduction of laterite ore in the molten state at 1723 K. The master Fe-Ni-Mo alloy was successfully produced at a lower temperature (1723 K). The liquidus of the slag decreased with the addition of oxide flux (Fe 2 O 3 and CaO) and that of the ferronickel alloy decreased with the addition of Mo/MoO 3 . More effective metal–slag separation was achieved at 1723 K, which reduces the smelting temperature by 100 K compared with the current electric furnace process. A small addition of Mo/MoO 3 not only decreased the melting point of ferronickel alloys but also served as a collector to aggregate the ferronickel sponges allowing them to grow larger. The FeO concentration in the slag and the nickel grade of the alloy decreased with increasing graphite reductant addition.

Description: Fluoride emissions during primary aluminum production are mitigated by dry scrubbing on alumina which, as the metal feedstock, also returns fluoride to the pots. This ensures stable pot operation and maintains process efficiency but requires careful optimization of alumina for both fluoride capture and solubility. The Brunauer-Emmett-Teller (BET) surface area of 70–80 m 2  g −1 is currently accepted. However, this does not account for pore accessibility. We demonstrate using industry-sourced data that pores 〈3.5 nm are not correlated with fluoride return. Reconstructing alumina pore size distributions (PSDs) following hydrogen fluoride (HF) adsorption shows surface area is not lost by pore diameter shrinkage, but by blocking the internal porosity. However, this alone cannot explain this 3.5 nm threshold. We show this is a consequence of surface diffusion-based inhibition with surface chemistry probably playing an integral role. We advocate new surface area estimates for alumina which account for pore accessibility by explicitly ignoring 〈3.5 nm pores.

Description: Selective recovery of lithium from four kinds of cathode materials, manganese-type, cobalt-type, nickel-type, and ternary-type, of spent lithium ion battery was investigated. In all cathode materials, leaching of lithium was improved by adding sodium persulfate (Na 2 S 2 O 8 ) as an oxidant in the leaching solution, while the leaching of other metal ions (manganese, cobalt, and nickel) was significantly suppressed. Optimum leaching conditions, such as pH, temperature, amount of Na 2 S 2 O 8 , and solid/liquid ratio, for the selective leaching of lithium were determined for all cathode materials. Recovery of lithium from the leachate as lithium carbonate (Li 2 CO 3 ) was then successfully achieved by adding sodium carbonate (Na 2 CO 3 ) to the leachate. Optimum recovery conditions, such as pH, temperature, and amount of Na 2 CO 3 , for the recovery of lithium as Li 2 CO 3 were determined for all cases. Purification of Li 2 CO 3 was achieved by lixiviation in all systems, with purities of the Li 2 CO 3 higher than 99.4%, which is almost satisfactory for the battery-grade purity of lithium.

Description: Li 2 O–MgO–TiO 2 ternary system is an important microwave dielectric ceramic material with excellent properties and prospect in both scientific research and application. A phase diagram of the Li 2 O–MgO–TiO 2 ternary system was established in this article, based on earlier research results and our present work. Microwave dielectric properties with compositions in different regions of the phase diagram have been analyzed. We found that the 0.33 Li 2 MgTi 3 O 8 –0.67 Li 2 TiO 3 ceramics sintered at 1200°C exhibited excellent dielectric properties: Q × f value = 80 476 GHz (at 7.681 GHz), ε r = 24.7, τ f = +3.2 ppm/°C. We also designed two ceramic systems in the Li-rich region of the Li 2 O–MgO–TiO 2 ternary system, which received little attention in the past decades, because many excellent single-phase ceramics, such as Li 2 MgTiO 4 , Li 2 MgTi 3 O 8 and MgTiO 3 , have been found in the Ti-rich region. The ceramic systems have low sintering temperatures but also relatively poor dielectric properties.

Description: Through a careful composition design, new oxyfluoride glass-ceramics (GCs) containing BaLiF 3 nanocrystals with sizes of around 30 nm were prepared. Microstructural characterizations show interpenetrating phase separation in the sample with a composition of 15BaF 2 –15ZnF 2 –70SiO 2 , after thermal treatment at 580°C for 40 h which leads to the nanocrystallization of BaLiF 3 . The BaLiF 3 nanocrystals embedded in the glassy matrix could provide Ba or Li sites for the incorporation of optically active rare earth and transition-metal ions, which provides a possibility to explore novel photonic properties by the codoping of rare earth and transition-metal ions in GC materials.

Description: The process–microstructure relationship in suspension plasma spray (SPS) of yttria partially stabilized zirconia (YSZ) has been studied experimentally. An ethanol-based suspension with a powder loading of 25 wt% was plasma sprayed with radial injection under four different plasma conditions, to examine the effects of plasma gas composition (Ar/He ratio), secondary gas (Ar/He and Ar/H 2 ), and the nozzle diameter of the plasma gun. The suspension feeding rate was optimized firstly and coatings were prepared for microstructural observation. Capturing of in-flight particles into water as well as collection of splats formed on heated flat metal substrates were utilized in order to better understand the more complicated intermediate process steps in SPS. It was found that a plasma jet with higher momentum allowed a higher suspension flow rate and both columnar and deep vertically cracked structure could be created depending on the plasma parameters as well as the substrate surface roughness.

Description: CsPbBr 3 quantum dots were precipitated in phosphate glasses through heat treatment. Controlled formation of CsPbBr 3 quantum dots was realized by adjustment of heat-treatment conditions. Absorption and photoluminescence spectra of CsPbBr 3 quantum dots were tuned from 432 to 521 nm. Upon ultraviolet or blue light excitation, efficient photoluminescence from these CsPbBr 3 quantum dots doped phosphate glasses was observed.

Description: The Static Current Density–Electric Field characteristics of Sr(MnTi) x Fe (12-2x) O 19 ferrite compositions ( x = 0.5, 1.0, 1.5, and 2.0) have been investigated from 4.15 to 36.30 kV/m at room temperature. Ohmic and nonohmic regions are observed at low and high field regimes. The various models, governing nonlinear conduction, are discussed qualitatively in terms of Space charge limited current (SCLC), Ionic hopping, Poole–Frenkel, Schottky–Richardson, and Fowler–Nordheim mechanisms. The results depict Child-Langmuir type SCLC in the investigated compositions.

Description: Disperse fine equiaxed α-Al 2 O 3 nanoparticles with a mean particle size of 9 nm and a narrow size distribution of 2–27 nm were synthesized using α-Fe 2 O 3 as seeds and isolation via homogeneous precipitation-calcination-selective corrosion processing. The presence of α-Fe 2 O 3 acting as seeds and isolation phase can reduce the formation temperature to 700°C and prevent agglomeration and growth of α-Al 2 O 3 nanoparticles, resulting in disperse fine equiaxed α-Al 2 O 3 nanoparticles. These α-Al 2 O 3 nanoparticles were pressed into green compacts at 500 MPa and sintered first by normal sintering to study their sintering behavior and finally by two-step sintering (heated to 1175°C without hold and decreased to 1025°C with a 20 h hold in air) to obtain nanocrystalline α-Al 2 O 3 ceramics. The two-step sintered bodies are nanocrystalline α-Al 2 O 3 with an average grain size of 55 nm and a relative density of 99.6%. The almost fully dense nanocrystalline α-Al 2 O 3 ceramic with finest grains achieved so far by pressureless sintering reveals that these α-Al 2 O 3 nanoparticles have an excellent sintering activity.

Description: This study presents an interesting phenomenon of the simultaneous occurrence of adsorption and synthesis of Mg–Al layered double hydroxide (Mg–Al–LDH) by stirring a precursor in an aqueous solution with methyl orange (MO) as target adsorbate with the precursor prepared by first milling Mg(OH) 2 for 1 h followed by another 3 h milling with Al(OH) 3 .The prepared precursor and LDH samples were characterized by a set of analytical methods including X-ray diffraction (XRD), thermogravimetry/differential scanning calorimetry (TG–DSC), and Fourier-transform infrared (FT–IR). The maximum adsorption capacity ( Q m ) of MO by the prepared precursor sample was 1110.2 mg/g, much higher than that from the synthesized LDH sample. Engineering application may be expected from the easy preparation of such precursor as adsorbent to purify the tremendous amounts of dye wastewater.

Description: A multicomponent multiphase solidification model has been developed to predict macrosegregation of steel ingots in three dimensions. The interpenetrating continua of liquid melt and solid grains is coupled with air for the mass, momentum, concentration, and heat transfer. Interfacial solute constraint relationships are derived to close the model by solving the solidification paths of multicomponent alloy. The upward unidirectional solidification case of a ternary Al-6.0 wt.%Cu-1.0 wt.%Si alloy is taken as a basic validation. Predictions have well captured the inverse segregation profiles induced by shrinkage during solidification. Then, the model is applied to a 36-ton steel ingot, which was experimentally investigated by temperature recording and concentration analysis. Predictions have reproduced the macrosegregation patterns in the measurements. Confidence levels of current predictions compared to the concentration measurements have been presented. General good agreements are exhibited in quantitative comparisons between measurements and predictions of carbon and sulfur variations along selected positions.