Sub-grain boundary migration in aluminium

Abstract

Observations on the migration of sub-grain boundaries during high-temperature testing of aluminium are presented. It is shown that the migration contributes significantly to the overall strain rate of the specimen and that the stress dependence and temperature dependence are in accord with the macroscopic strain rate, and are strictly related to the deformation contribution from fine slip. The mobility of the sub-boundaries leads to a new understanding of the dynamic equilibrium of the sub-structure and its stability with respect to recrystallization. It further leads to the possibility of sub-boundaries acting both as effective obstacles to deformation and as sources of internal stress.