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  • 1
    Publikationsdatum: 2024-04-11
    Beschreibung: The initial temper may directly affect the deformation behavior and material performance in creep age forming (CAF) process. Five heat treatment states are selected as the initial tempers for CAF, namely, solution, peak-aging (T6), over-aging (T73), retrogression and re-solution. The formability and performance of an Al-Zn-Mg-Cu alloy with the above initial tempers in creep aging process are investigated via using creep and stress relaxation aging tests, mechanical property tests, corrosion resistance tests and microstructure analysis. The differences of formability are attributed to the inhibitions of different distributed matrix precipitates (MPts) on the dislocation movement, namely, the more coarsening the MPts is, the easier the dislocation movement. During creep aging process, the mechanical properties are improved for the solution, retrogression and re-solution tempers with fine MPts, but reduced for the T6 and T73 tempers due to coarsening of MPts. Since the distribution of grain boundary precipitates (GBPs) becomes discontinuous, the corrosion resistances of the creep aged specimens are enhanced for all initial tempers. Taking both mechanical properties and corrosion resistances into account, the re-solution temper may be a preferable choice to achieve high performance of the components beyond the precise shape in CAF.
    Schlagwort(e): Al-Zn-Mg-Cu alloy, creep age forming, initial temper, precipitate, formability, mechanical property, corrosion resistance ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TD Industrial chemistry and manufacturing technologies::TDP Other manufacturing technologies::TDPM Metals technology / metallurgy
    Sprache: Englisch
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    Format: image/jpeg
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 532-533 (Dec. 2006), p. 141-144 
    ISSN: 1662-9752
    Quelle: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Thema: Maschinenbau
    Notizen: Guide rolls play an important role in controlling both the ring circularity and the stability ofcold ring rolling process. However, it is difficult to predict and control the motion of the guide rollsdue to the complexity of process associated with the coupled effects of multi-factors. In this paper, areasonable controlling model of the guide rolls is proposed, and the functional relationship betweenthe motion track of the guide rolls and their setup parameters and process ones is established, bywhich the guide rolls motion track can be determined. On this basis, a 3D-FE simulation model forcold ring rolling is developed under the ABAQUS software environment and the effects of the initialposition and motion track of the guide rolls on the forming stability, ring circularity, rolling force, andoscillating are investigated. Taking the forming stability and ring circularity as objects, the optimuminitial position and motion track of the guide rolls are obtained
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 532-533 (Dec. 2006), p. 149-152 
    ISSN: 1662-9752
    Quelle: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Thema: Maschinenbau
    Notizen: Cone spinning is an advanced but complex metal forming process under coupled effectsof multi-factors. Understanding the deformation mechanism, i.e., the stresses, strains, and metalflow in the deformation zone during the process is of great significance for optimizing the spinningprocess and controlling the product quality. In this paper, based on ABAQUS/Explicit, a reasonableFEM model for cone spinning with a single roller has been established, and the features of stress,strain and wall thickness during the process have been obtained. The results show the following: (1)In the beginning, large stress, large strain and the acute thinning of wall thickness localize at thesmall region below the roller, then the region extends into a small ring, further it becomes a largering, and finally the ring will become uneven if the wrinkling occurs in the flange. (2) Afterspinning, the acute thinning region locates at the midst of the wall near the bottom of the workpiece.(3) At earlier stage of cone spinning, as a result of the acute thinning of wall thickness in the wallzone, the unevenness of wall thickness increases sharply to a value, then it almost keeps the value atthe stable stage, and finally it will slowly increase again if the wrinkling appears in the flange. Theresults are helpful for determination and optimization of process parameters of cone spinning
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 532-533 (Dec. 2006), p. 205-208 
    ISSN: 1662-9752
    Quelle: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Thema: Maschinenbau
    Notizen: Establishing a reasonable mechanical model for multi-pass conventional spinning andtypical drawing spinning is the object of the present study. Research on stress and strain distributionduring multi-pass conventional spinning processing under three modes of roller motion, i.e.,one-way moving without profiling, one-way moving with profiling, and two-way moving withprofiling, is carried out using elasto-plastic FEM method. Though the equivalent stress distributionunder these three modes of roller motion is similar, there exists significant difference in magnitude,with the equivalent stress in the close-mandrel area being the highest in the case of profiledone-way moving. As far as the strain is concerned, it has a similar distribution as the equivalentstress, with the strain in the close-mandrel area under one-way moving with profiling having thehighest value. In the case of roller two-way moving with profiling, the strain distribution is the mosthomogeneous, while the work-hardening of the blank is the most serious. In all cases, both stressand strain in the deforming zone increase with increasing spinning passes
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 546-549 (May 2007), p. 833-838 
    ISSN: 1662-9752
    Quelle: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Thema: Maschinenbau
    Notizen: The clearance and friction have large influence on wrinkling in rotary draw bendingprocess of thin-walled rectangular tube. In this paper, a three-dimension Al FEM model of rotarydraw bending of thin-walled rectangular tube is built under the ABAQUS/ Explicit environment.Based on the model, simulation and analysis of rotary draw bending for aluminum alloy 3A21thin-walled rectangular tube have been carried out. The results show that the height of wrinkling wavedecreases obviously with the decrease of the clearance between mandrel and tube or with the increaseof the friction coefficient between wiper die and tube; however, the effect of friction coefficient onwrinkling becomes weaker while increasing the clearance between mandrel and tube. Theachievements of this study provide a guideline for determining the process parameters for thin-walledrectangular tube in rotary draw bending process
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 561-565 (Oct. 2007), p. 1813-1817 
    ISSN: 1662-9752
    Quelle: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Thema: Maschinenbau
    Notizen: Material behaviors of anisotropy and rate sensitivity affect cold ring rolling greatly. So, aself-developed incremental model of rate dependent crystal plasticity (RDCP) is utilized to forecastthe deformation characteristics of this forming process based on a 3D FE model underABAQUS/Explicit environment. The results show that the model of RDCP captures materialbehaviors of anisotropy and rate sensitivity better in this forming process by the comparison with themodel of J2 plasticity; with the decrease of rate sensitivity coefficient, the forming process becomesmore unstable with smaller rolling force and growth in ring radial direction; with the increase of feedrate of idle roll, the deformation of ring becomes more even while the rolling force becomes larger
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 561-565 (Oct. 2007), p. 831-834 
    ISSN: 1662-9752
    Quelle: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Thema: Maschinenbau
    Notizen: A blade with a damper platform, with excellent anti-vibration characteristic and highefficiency, has become one of the most important types of blades being developed in the aeronauticalengines. During the precision forging process of this blade, the friction between dies and workpiecehas important effects on metal flow, deformation defects, load and energy etc. So researching theeffects of friction conditions on the forging process of blade with a damper platform has been a crucialproblem urgent to be resolved. In this paper, the precision forging process of titanium alloy blade witha damper platform under different friction conditions has been simulated and analyzed based on theDEFORM-3D software platform. The obtained results reveal the influence laws of friction ontemperature field and load-stroke curves, and provide a significant basis for determiningtechnological parameters of the blade forging process
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 575-578 (Apr. 2008), p. 367-372 
    ISSN: 1662-9752
    Quelle: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Thema: Maschinenbau
    Notizen: Nowadays, 3D-FE Modeling and simulation is an indispensable method for the optimumdesign and precise control of radial-axial ring rolling process for its complexities. In this paper, theunique forming characteristics of radial-axial ring rolling have first been summarized, and thensome key technologies for 3D-FE modeling of the process have been presented and their solutionschemes have been given out, lastly the modeling and simulation of radial-axial ring rolling processhave been realized using elastic-plastic dynamic explicit procedure under ABAQUS environment.The work provides an important basis and platform for the future investigations, such as formingmechanism and laws, process optimum design and precise control
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 575-578 (Apr. 2008), p. 579-583 
    ISSN: 1662-9752
    Quelle: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Thema: Maschinenbau
    Notizen: In-plane bending is an advanced plastic processing technology which controls the unevencompressing plastic deformation of strip metal harmoniously and forces the strip metal to producein-plane bending and to form an open circle. In-plane bending is divided into incremental andcontinuous process according to the loading manner. While much attention has been paid to thecontinuous in-plane bending techniques and achievements have been made at home and abroad, onlylimited experimental investigation has so for been done on incremental in-plane bending by overseasscholars. In this paper, a 3D finite element simulation based on the rigid-plastic principle is performedfor incremental in-plane bending of pure aluminum sheet with width of 25 ~ 27.5 mm, thickness of1.5 ~ 3 mm. Influences of technical parameters such as punch inclined angle αp, punch indentation s,thickness of strip t0, width of strip w0 and strip pitch p on the strip bending radius Rin are studied. Theachievement of this study enriches the uneven deformation theory. It lays a theoretical foundation forgeneralization and industrialization of incremental in-plane bending and offers a new idea to theresearch and development of the advanced plastic processing technologies
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 561-565 (Oct. 2007), p. 805-808 
    ISSN: 1662-9752
    Quelle: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Thema: Maschinenbau
    Notizen: During cold ring rolling process, the accurate prediction and analysis of force and powerparameters, including roll force (RF) and roll moment (RM), is important in selecting, designing anddeveloping the forming rolls and cold ring rolling mills. In this paper, a three-dimensionalelastic-plastic dynamic explicit FE model of cold ring rolling process has been presented andvalidated in terms of roll force and geometry development. Based on the model, the variation laws offorce and power parameters under different sizes of forming rolls (including driver roll and idle roll)and forming parameters (including the rotational speed of driver roll 1 n and the feed rate of idle rollv ) have been revealed by comprehensive numerical simulations
    Materialart: Digitale Medien
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