The temperature dependence of yield

A theoretically rigorous expression is derived from the fundamental equation of rate processes to describe the temperature dependence of the upper and lower yield stress in terms of physical quantities. The effect of the activation volume and activation energy on the yield behavior was investigated over a wide temperature range. The analysis shows that the yield stress is a sensitive function of the temperature when the activation volume is small and that the temperature sensitivity is relatively weak at activation volumes V _f>10³ b ³. The theory predicts that the yield drop has a maximum at an intermediate temperature range and vanishes both at very low and very high temperatures. The calculated behavior was found to be in good qualitative agreement with the results of the measurements obtained by several investigators. It is concluded that the proposed theory can explain fully the temperature dependence of the yield behavior.