AZ91镁合金的热力行为和显微组织演化

摘要

研究AZ91镁合金在热压缩过程中的流变行为和显微组织演化.在350～425℃对试样进行热压缩变形.在应变速率为0.1 s-1时,应变分别为峰应变、0.3和0.5.使用光学和扫描电子显微镜研究显微组织的演化.结果表明,在压缩过程中再结晶晶粒沿预先存在的晶界形核;动态再结晶晶粒的数量随着应变的增大呈指数增加,且服从Avrami方程;动态再结晶晶粒的尺寸在开始时增大,达到最大值后开始减少.%The flow behavior and microstructure evolution of AZ91 magnesium alloy during a thermomechanical process,hot compression test,was investigated.The specimens were hot compressed at a temperature ranging from 350 ℃ to 425 ℃ and at strain rate of 0.1 s-1 to the strains of 0.3,0.5 and peak.Microstructural evolutions were studied using optical and scanning electron microscopes.The results show that during the compression process,the recrystallized grains nucleate along the pre-existing grain boundaries.The amount of dynamically recrystallized grains is increased with strain in a sigmoid scheme followed by Avrami equation.The size of dynamically recrystallized grains also increases at the beginning and decreases after reaching the maximum value.