【摘要】 采用空气锤在300℃下对AZ31镁合金进行多向锻造成形,并在200～400℃下进行退火处理,采用金相显微镜、电子背散射衍射和X射线衍射仪观察AZ31镁合金的微观组织,并对其力学性能进行测试。结果表明,多向锻造成形过程中,■拉伸孪生和■二次孪生是主要的孪生机制,当累积应变ΣΔε=0.96时,由于孪生诱发动态再结晶的作用,合金组织迅速细化至7.8μm,合金表现出优异的综合力学性能,抗拉强度、屈服强度和延伸率分别为320.3 MPa、218.5 MPa和30.3%;锻造合金经退火处理后,晶粒发生明显长大,双峰基面织构演变为典型板织构,晶粒尺寸和织构强度均随退火温度和时间增加而增大,合金强度和延伸率则随退火温度升高而下降。更多还原

【Abstract】 AZ31 magnesium alloy was subjected to multiple forging at 300 ℃ by using pneumatic hammer, followed by annealing at 200～400 ℃. Its microstructure was analyzed by using optic microscopy, electron back-scatter diffraction and X-ray diffraction, and its mechanical properties were tested. The results show that the ■ extension twin and ■ secondary twin are the dominant twinning mechanism during the multiple forging process. When the accumulative strain ΣΔε=0.96, the grain of alloy is quickly refined to 7.8 μm due to the dynamic recrystallization induced by twining and the alloy presents excellent comprehensive mechanical properties, with tensile strength, yield strength and elongation coefficient of 320.3 MPa, 218.5 MPa and 30.3%, respectively. After the annealing of the forged alloy, the grain size increases obviously and the bimodal basal texture has evolved into a plate texture, with both grain size and texture strength improved with the rising of the annealing temperature and prolonging of annealing time, but alloy strength and elongation reduced with the rising of the temperature.更多还原