1998 Volume 39 Issue 12 Pages 1255-1263
Deformation and recrystallization during hot working of some polycrystalline metals have been described with a kinetic equation on deformation and Avrami equation respectively. Based on the interactions between deformation region and recrystallization region, a nonlinear differential equation group is suggested to be the kinetic model of hot working. According to the analyses on the stability of the solution of the equation group, if the working temperature, strain rate and other parameters satisfy certain conditions, the volumes of deformation region and recrystallization region will change cyclically and alternatively, which can cause a special fluctuation of the stress-strain curve. The amplitude of the fluctuation will decrease gradually with the increasing strain, when a dynamic equilibrium of deformation and recrystallization is formed finally, a stable stress-strain relation can be expected. A formula is proposed to calculate the frequency of the fluctuation, it can increase with the increasing working temperature or with the decreasing strain rate, initial grain size or solute atoms content. However, when working temperature, strain rate and other parameters go over the critical conditions, the fluctuation of macro-stress can not occur. The calculated results are in better agreement with experiments, and some phenomena associated with dynamic recrystallization can be reasonably explained.
