挤压铸造AZ81镁合金的凝固行为及固溶时效处理

Solidification Behavior and Solution and Aging Treatment of Squeeze Casting AZ81 Magnesium Alloy

研究了挤压铸造AZ81镁合金的显微组织及力学性能,描述了合金在挤压铸造过程中的凝固行为,研究了热处理对合金显微组织和力学性能的影响。结果表明,挤压铸造AZ81镁合金的显微组织由α-Mg初晶和高度弥散的α-Mg+β-Mg17Al12二元共晶组织组成,α-Mg初晶的体积分数随远离模具表面而逐渐增加。合金经400℃×12 h固溶+200℃×8h时效处理后,合金的抗拉强度和断裂伸长率相对挤压铸造态分别提高了16.07%和11.02%。

The microstructure and mechanical properties of squeeze casting AZ81 magnesium alloy were investigated. The solidification behavior of the alloy during the squeeze casting process was characterized. The effects of heat treatment on microstructure and mechanical properties of squeeze casting AZ81 magnesium alloy were investigated. The results show that： the microstructure of squeeze cast specimen is consists of primary α-Mg and highly dispersed α-Mg ＋β-Mg17TAl12 binary eutectics. The volume fi＇action of primaryα-Mg increases with the increase of distance away fi＇om the surface of die. After the 400℃×12 h solution and 200℃×8 h aging treatment, the ultimate tensile strength and elongation of the alloy respectively increase 16.07% and 11.02% than that of squeeze casting.