Effect of Annealing Temperature on Grain Growth Process in Al-0.3 mass%Mg Alloy

Grain growth behavior of an Al-0.3 mass%Mg alloy was investigated focusing on annealing temperature dependence of the changes of grain orientation and local grain boundary character distribution (GBCD). Primary recrystallized specimens were isothermally annealed at 623 or 773 K and their microstructures were observed with an optical microscope and a SEM. Grain orientations and grain boundary structure were characterized using the SEM-ECP method. The texture change can be divided into two stages during annealing. At the first stage, the cube texture developed as grain growth proceeded. Then, the cube texture declined with the development of these grains accompanied by remarkably abnormal growth of non cube grains at the second stage. This tendency was accelerated at lower temperature. The cause of abnormal growth of non cube grains is discussed with the change of local GBCD and the temperature dependence of grain boundary energies at the triple junction.