The evolution of coarse grains and its effects on weakened basal texture during annealing of a cold-rolled magnesium AZ31B alloy

Abstract

The nucleation, grain growth of 34 coarse grains during annealing were tracked using a quasi-in-situ EBSD method. These 34 coarse grains had different orientations and most grains were non-basal orientated. No preferable grain growth or special types of grain boundaries were identified. Only 9 coarse grains nucleated from deformed grain boundaries due to initial large grain size and limited grain boundary volume fraction. The main nucleation site of 34 coarse grains was dislocation cells or subgrains in deformed grain interiors. Their recrystallisation behaviour can be illustrated by abnormal subgrain growth (AsGG) rarely reported in Mg alloys. The coarse basal grains showed no growth advantage in terms of grain size or number over other non-basal grains, leading to a weak basal texture in AZ31B alloy.

Keywords

• Magnesium alloy
• EBSD
• Annealing
• Recrystallisation
• Grain growth