Microstructure and properties regulation of solution-treated Mg-6Al-1Zn alloy via high-speed rolling

Magnesium alloys have the characteristics of light weight and high specific strength, and can be used in aerospace equipment, automobile, and other fields. How to refine the microstructure of magnesium alloys and optimize their processing techniques is a problem that must be solved for their production and application in manufacturing. When traditional room-temperature rolling is applied to solution-treated Mg-6Al-1Zn alloy (AZ6l) sheets with a large reduction, sheet fracture occurs. In view of this, this work proposes a multi-pass high-speed rolling and inter-pass annealing technique. Specifically, solution-treated AZ6l alloy is subjected to multi-pass high-speed rolling at 400°C and a rolling speed of 1, 100 m/min, with inter-pass annealing, to achieve a large reduction rolling of 79% and refine the large grains in the solution-treated state. The results show that during rolling, the sheet microstructure generates a large number of twins, undergoes dynamic recrystallization (DRX), and precipitates nano-scale Mg 17 Al 12 phases. Inter-pass annealing leads to complete static recrystallization, forming equiaxed grains, whose size decreases with the increase of passes. The microhardness of both as-rolled and annealed sheets increases with the number of rolling passes.