ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The steady state creep of polycrystalline (5–60 μm) rutile, which is doped with 1 cation % tantalum, is controlled by a Nabarro-Herring lattice diffusion process at 1100 to 1200° C. Doping with tantalum significantly depresses the steady state creep rate by lowering the concentrations of titanium interstitials and oxygen vacancies. The concentrations of these defects, and hence the steady state creep rate of doped rutile, can be increased by decreasing the oxygen partial pressure below 10−7 to 10−8 atm at 1200° C. Tentative evidence is presented in support of the hypothesis that the steady state creep of polycrystalline, undoped rutile at 950 to 1100° C is controlled by interfacial defect creation and/or annihilation at grain boundaries. Interfacial controlled deformation rates are probably due to the large concentrations (and perhaps high mobilities) of cation and anion lattice defects which are present in pure rutile equilibrated in both oxidizing and reducing atmospheres. The steady state creep rate was a very weak inverse function of the grain size and essentially independent of the oxygen partial pressure.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00542065
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