Si及Sb对铸态Mg-Al-Si合金组织和力学性能的影响

Effects of Si and Sb on microstructures and mechanical properties of as-cast Mg-Al-Si alloys

用普通铸造法制备不同Al、Si含量的Mg-Al-Si三种合金,研究了Si含量和微量Sb对合金组织和力学性能的影响。结果表明:随着Si含量增加,合金中的Mg2Si逐渐变粗大,合金力学性能逐渐提高。添加0.75%Sb后,三种合金均产生Mg3Sb2相,粗大的Mg2Si得到细化,呈相对弥散分布,合金的屈服强度和抗拉强度进一步提高。拉伸断裂形式为准解理脆性断裂。

Three kinds of Mg-Al-Si alloys with different Al and Si content are prepared by the gravity casting .Effects of Al and Si contents on Microstructure andmechanical propertiesat room temperature of the ascast alloys are investigated .The results show that the Mg 2 Si becomes bulky by increasing Si content in alloy and the hardness ,yield strength and ultimate tensile strength of alloys increases .The Mg3 Sb2 phase is formed in the microstructures of alloys after adding 0.75%Sb.The Mg2 Si particle gradually gets refined and shows a relative dispersion distribution in matrix （α-Mg ） , which further increases the tensile strength and the yield strength of alloys .The fracture of the alloys is characterized by quasi-cleavage brittle .