摘要
Superplastic mechanical properties of fine-grained AZ31 Mg alloy sheets in the temperature range of 250450 ℃ and strain rate range of 0.7×10-31.4×10-1 s-1 were investigated by uniaxial tensile tests. The microstructure evolution during the superplastic deformation of AZ31 Mg alloy was examined by means of metallurgical microscope and transmission electronic microscope (TEM). It is shown that, fine-grained AZ31 Mg alloy starts to exhibit superplasticity at 300 ℃ and the maximum elongation of 362.5% is obtained at 400 ℃ and 0.7×10-3 s-1. The predominate superplastic mechanism of AZ31 Mg alloy in the temperature range of 300400 ℃ is grain boundary sliding (GBS). Twinning caused by pile-up of dislocations during the early stage of superplastic deformation is the hardening mechanism, and dynamic continuous recrystallization (DCRX) is the important softening mechanism and grain stability mechanism during the superplastic deformation of the alloy.
Superplastic mechanical properties of fine-grained AZ31 Mg alloy sheets in the temperature range of 250450 ℃ and strain rate range of 0.7×10^(-3)1.4×10^(-1) s^(-1) were investigated by uniaxial tensile tests. The microstructure evolution during the superplastic deformation of AZ31 Mg alloy was examined by means of metallurgical microscope and transmission electronic microscope (TEM). It is shown that, fine-grained AZ31 Mg alloy starts to exhibit superplasticity at 300 ℃ and the maximum elongation of 362.5% is obtained at 400 ℃ and 0.7×10^(-3) s^(-1). The predominate superplastic mechanism of AZ31 Mg alloy in the temperature range of 300400 ℃ is grain boundary sliding (GBS). Twinning caused by pile-up of dislocations during the early stage of superplastic deformation is the hardening mechanism, and dynamic continuous recrystallization (DCRX) is the important softening mechanism and grain stability mechanism during the superplastic deformation of the alloy.
出处
《中国有色金属学会会刊:英文版》
CSCD
2004年第6期1100-1105,共6页
Transactions of Nonferrous Metals Society of China
关键词
AZ31镁合金
超塑性
微观结构变化
再结晶
AZ31 Mg alloy
superplasticity
microstructure evolution
dynamic recrystallization