Deformation Behavior and Microstructure Evolution of AZ61 Magnesium Alloy during Hot Compression

Hot compression of AZ61 magnesium alloy was conducted on Gleeble-1500 thermal compression tester at 250-400 ℃ in the strain rate range of 0.001-10 s-1, and the hot compression deformation behavior and microstructure evolution were investigated. The results show that the flow behavior of AZ61 alloy during hot compression could be described by Arrhenius relation. The hot deformation activation energy and stress exponent were 147.262 kJ·mol-1 and 5.096, respectively. The dynamic recrystallization (DRX) extent increased with strain rate increasing at the same compression temperature. DRX developed mainly at grain boundaries at the lower strain rate of 0.001-1 s-1, and DRX developed extensively at grain boundaries and twins at the higher strain rate of 10 s-1. The DRX extent and the average grain size of DRX grains both increased with deformation temperature increasing at the same strain rate.