On the basis of dislocation theory, an investigation was made of the mechanism of the strain-rate effect. Strain-rate effects and dislocation motion were bridged by Orowan's relationship, and the stress dependence of the dislocation velocity was considered to be the dynamic relationship of dislocation motion. The mechanism of the strain-rate effect was then investigated qualitatively by using these two relationships, even though the kinematics relationship of dislocation motion was absent due to complicated styles of dislocation motion. The present analyses agreed with existing experimental results. Based upon the analyses, it was proposed that strain-rate criteria, rather than stress criteria, should be satisfied when a metal was fully yielding at a given strain rate.

Mechanism of Strain Rate Effect Based on Dislocation Theory. K.Qin, L.M.Yang, S.S.Hu: Chinese Physics Letters, 2009, 26[3], 036103