On the role of grain boundary character distribution in grain growth of Al-Mg alloys

Grain growth behaviour of recrystallized Al-Mg alloys containing 0.3 and 2.7mass%Mg was investigated, focusing on the interconnection between development of the texture and grain boundary character distribution. An Al-0.3mass%Mg alloy showed two stages in the change of microstructure during grain growth: the frequency of cube oriented grains and the Σ1 boundary significantly increased at an early stage and then decreased. In the second stage a small amount of isolated large grains with the non-cube component grew and consumed the surrounding cube grains. In contrast, the frequency of cube oriented grains and the grain boundary character distribution showed no significant change during grain growth of Al-2.7mass%Mg. Small clusters composed of several cube grains containing Σ1 boundaries were formed and their spatial distribution played an important role in the change of microstructure during grain growth. The effect of the spatial distribution on the grain growth behaviour was discussed considering the energy balance at triple junctions of grain boundaries.