第二相粒子对ECAP挤压的2A12铝合金晶粒细化的影响

采用等径角挤压技术对2A12铝合金在室温下进行挤压,成功制备了亚微米尺度的块体铝合金材料.挤压前材料的平均晶粒尺寸约5μm,两次挤压后,平均晶粒尺寸细化至200nm左右.合金中的Al2Cu相在挤压过程中由针状变成了块状颗粒,而Al2CuMg相在挤压过程中晶粒大小基本不变.研究发现,硬颗粒Al.2CuMg对基体α-Al有剪切和割裂作用,可以促进基体的晶粒细化过程,并初步给出了晶粒细化的模型.

The sub-micrometer 2A12 aluminum alloy has been successfully prepared through Equal Channel Angular (ECA) pressing. The average grain size of 2A12 aluminum alloy before pressing is about 5 μm. And it turns to 200 nm after twice ECA pressing. During the course of pressing, the needle-like Al2Cu phase turns to block. There is no change of grain size for Al2CuMg phase. It is found that Al2CuMg phase has the effect of shear and cut on α-Al matrix, and that it can accelerate the grain refinement of α-Al matrix. The primary model of grain refinement is presented. (