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采用Gleebe-1500热/力模拟机研究了 Mg-5.6Zn-0.7Zr-0.8Nd合金在应变速率为0.1,0.01和0.002s~(-1)、变形温度为373—673K、最大变形程度60％条件下的高温塑性变形行为。分析了合金流变应力与应变速率、变形温度之间的关系,计算了高温变形时变形激活能和应力指数,并观察了合金变形过程中显微组织变化情况。结果表明:Mg-5.6Zn—0.7Zr-0.8Nd合金在热变形过程中不同温度下流变应力呈现不同形式,分析可知加工硬化、动态回复和动态再结晶在不同温度和不同应变速率下各自起到了重要的作用,合金变形激活能随应变速率增加而升高.在473K温度以上变形,合金发生明显动态再结晶且动态再结晶晶粒非常细小,晶粒尺寸为 5—10μm,从而可明显提高合金的塑性
The mechanical properties of Mg-5.6Zn-0.7Zr-0.8Nd alloy at strain rates of 0.1, 0.01 and 0.002s ~ (-1), deformation temperature of 373-673K and maximum deformation of 60% were studied by Gleebe-1500 thermal / Under high temperature plastic deformation behavior. The relationship between flow stress and strain rate and deformation temperature was analyzed. The deformation activation energy and stress index at high temperature deformation were calculated. The variation of microstructure during deformation was also observed. The results show that the flow stress of Mg-5.6Zn-0.7Zr-0.8Nd alloy presents different forms at different temperatures during the hot deformation. It can be seen from the analysis that work hardening, dynamic recovery and dynamic recrystallization play different roles at different temperatures and different strain rates An important role in the alloy deformation activation energy increases with the increase of strain rate.At 473K temperature deformation, the alloy significant dynamic recrystallization and dynamic recrystallization of the grain is very small, the grain size of 5-10μm, which can significantly improve the alloy Plasticity