HIGH TEMPERATURE DEFORMATION OF RUTILE.
UTAH UNIV SALT LAKE CITY
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Steady state, four-point bending strain rate measurements were made on 44 single crystal TiO2 specimens in the temperature range of 1100C to 1230C under controlled partial pressures of oxygen. The results show the complexity of creep in a limited temperature range with a varia tion in stoichiometry and impurity concentration. Recent literature indicates that the predominant lattice defect in non-stoichiometric TiO2 is probably the titanium interstitial rather than oxygen vacancies, as had been generally thought. The time required to reach a constant defect concentration, measured as part of this experiment, disagrees with published diffusion data. The increase in activation energy for creep with a decrease in the partial pressure of oxygen appears to be at variance with the oxygen vacancy defect model. The importance of the various atomic processes which determine the values of the creep parameters, cannot be determined on the basis of creep measurements alone. This will be possible only after precise measurements of activation energies, etc., for these atomic processes are made. However, several possibilities can be ruled out on the basis of the creep data these are discussed, as are tentative models to explain variation in measured creep parameters. Author