半固态等温组织的特征
( 1. 西安理工大学 材料科学与工程学院， 西安 710048;
2. 西北工业大学 材料科学与工程学院， 西安 710072)
摘 要: 研究了AZ91D镁合金在应变诱发熔化激活法处理过程中形变率和形变温度对组织的影响。结果表明： 形变温度为280℃时，随着形变率增加， 部分枝晶臂逐渐伸长， 枝晶破断现象加剧； 形变率为20%时，随着形变温度的提高， 组织的形变方式逐渐由以枝晶断裂为主转变为带有方向性的弯曲。 AZ91D合金在580℃等温10min所获得的半固态组织， 随着形变率增加，球状晶粒尺寸减小， 圆整度提高； 随形变温度的提高， 固相颗粒的偏聚现象减轻。
关键字: 应变诱发熔化激活法; 镁合金； 压缩形变； 半固态组织
microstructures of AZ91D alloy for upsetting in SIMA process
（ 1. School of Materials Science and Engineering,
Xi′an University of Technology,Xi′an 710048, China;
2. Department of Materials Science and Engineering,
Northwestern Polytechnical University, Xi′an 710072, China）
Abstract: The influences of strain and temperature on microstructure of AZ91D alloy for upsetting in the strain-induced melt activation process were investigated. The results indicate that with increasing the strain at 280℃, the dendrite arms of AZ91D alloy get broken or stretched-out. With increasing the predeformation temperature under 20% strain, the deformation style of the dendritic structure of AZ91D alloy changes gradually from fragmentation to directional bending. After held at 580℃ for 10min , the greater the strain, the finer and rounder the size of the globular grains of AZ91D alloy. And in the mean time, the higher the isothermal temperature, the less the agglomeration of solid particles.
Key words: train-induced melt activation; magnesium alloy; upsetting; semi-solid microstructure
