A simple 1-dimensional model was proposed for predicting the effects of the grain boundary migration which occurred during the hot-compression testing of polycrystalline specimens. Strain hardening, dynamic recovery, and grain boundary migration-induced softening were accounted for by using a modified Laasraoui¯Jonas equation. The movement of grain boundaries had 2 sources; convection driven by material flow, and migration induced by local dislocation-density differences. The disappearance of grains during straining led to changes in the local topology. By using parameters relevant to Al, it was shown that the average grain thickness tended to a steady-state value, while significant flow stress softening occurred. Both predictions were in agreement with experimental data. Moreover, the model permitted the true average migration rate to be simply estimated from grain thickness evolution.

Effects of Dynamic Grain Boundary Migration during the Hot Compression of High Stacking Fault Energy Metals. S.Gourdet, F.Montheillet: Acta Materialia, 2002, 50[11], 2801-12