铸态Mg-4Al-2Si合金的显微组织与力学性能

Microstructure and Mechanical Properties of As-cast Mg-4Al-2Si Magnesium Alloy

采用重力铸造法制备Mg-4Al-2Si(AS42)镁合金,研究了铸态合金的显微组织和室温力学性能。结果表明:铸态AS42合金主要由α-Mg基体、β-Mg17Al12相及Mg2Si相组成;β-Mg17Al12相呈网状和棒状分布于晶界上,粗大的汉字状Mg2Si相沿晶界或穿晶分布,多边形块状Mg2Si相随机分布于基体组织中。铸态合金的硬度为64.5 HV,室温抗拉强度为113.5 MPa,屈服强度为86 MPa,伸长率为4.1%;拉伸断裂形式为准解理脆性断裂。

Mg-4Al-2Si（AS42） magnesium alloys were prepared by the gravity casting.Microstructure and mechanical properties at room temperature of the as-cast AS42 alloy were investigated.The results show that the as-cast microstructure consists of α-Mg matrix,β-Mg17Al12 phase and Mg2Si phase.The network and rod shaped β-Mg17Al12 phase distribute on grain boundary,and the coarse Chinese script type Mg2Si particles distribute on grain boundary or transcrystallization,while the block-like Mg2Si distributes in matrix（α-Mg）.The hardness of the alloy is 64.5HV,ultimate tensile strength,yield strength and elongation are about 113.5,86MPa and 4.1% respectively.The fracture forms of the alloy is quasi-cleavage brittle fracture.