Mg-9Gd-4Y-0.6Mn合金在293～723 K时的变形行为及微观组织演变

研究Mg-9Gd-4Y-0.6Mn 合金在应变速率为0.01 s-1、变形温度为293～723 K时的压缩塑性变形行为, 并在光学显微镜下观察合金在不同变形温度下的表面滑移线及孪生变形形貌与内部微观组织. 研究结果表明： 合金流变应力应变曲线在不同温度呈现出不同的形状, 加工硬化、动态回复和动态再结晶在不同的温度各自起到了重要的作用;在523 K以上时非基面滑移已被激活, 形变孪生在296～723 K范围都存在, 在673 K以上出现动态再结晶;动态再结晶晶粒优先在原始晶界和粗大第二相粒子处形核, 同时在723 K还观察到晶界弓出形核和＂孪生＂动态再结晶现象.

Deformation behavior and microstructure evolution of Mg-9Gd-4Y-0.6Mn alloy at 293-723 K

The plastic deformation behavior of Mg-9Gd-4Y-0.6Mn alloy was investigated by compression at 293723 K and 0.01 s~(-1).The surface deformation relief and the internal microstructure of the alloy at different deformation temperatures were analysed by optical microscopy.The results show that the flow curves exhibit different shapes at different temperatures,and that work-hardening,dynamic recovery and dynamic recrystallization operate respectively at different temperatures.The non-basal slip is activated at above 523 K,twinning exits at 293723 K,and dynamic recrystallization appears at above 673 K.The dynamic recrystallization(DRX) grains nucleate preferentially at initial grain boundaries and coarse particles,and in addition the nucleation by bulging of initial grain boundaries and twinning DRX at 723 K are observed.