Strain rate and temperature dependence of yield stress of uranium dioxide

Specimens of polycrystalline UO2 have been strained in compression at constant strain rate from 0.05 to 10.0 /min and at temperatures from 9000 to 2,0000C. Results are presented showing the characteristics yield points and the variation of the yield stress with strain rate and temperature. The experimental data shows that the values of strain rate sensitivity and activation energy for yield flow of UO2 at high strain rate are greater than that of previous data which was given at usual strain rates. The data are discussed in relation to the mechanism which controls the yield strength of UO2. The yield strength at high strain rate may be controlled primarily by the Peierls stress. (auth.)