Mg-12Al-12Zn-2Si-0.5Ca-xSb合金的组织与力学性能

Microstructure and Mechanical Properties of Mg-12Al-12Zn-2Si-0.5Ca-xSb Magnesium Alloys

研究了Mg-12Al-12Zn-2Si-0.5Ca-xSb(x=0.2,0.4,0.6,0.8和1.0,质量分数,%)合金的显微组织与力学性能,重点讨论了Sb对Mg2Si颗粒的细化效果与细化机制。结果表明,在合金中加入微量Sb,形成的Mg3Sb2相作为异质形核核心,细化了Mg2Si相颗粒。随Sb含量从0.2%增加到1.0%,Mg2Si颗粒由粗大的骨骼状和花瓣状逐渐转变为相对细小的多边形状。当Sb含量为0.8%时,Mg2Si颗粒最大尺寸由原来的50μm减小至8μm。此时,合金抗拉强度、屈服强度和伸长率分别达到175.8MPa、167.6MPa和1.67%。合金室温拉伸断裂形式为准解理脆性断裂。

The microstructure and mechanical properties of Mg-12 Al-12 Zn-2 Si-0.5 Ca-xSb（x=0.2,0.4,0.6,0.8 and 1.0,mass fraction,%）alloys were investigated by OM,SEM and EDS,tensile testing.The refining effect and mechanism of Sb on Mg2 Si particles were described emphatically.The results show that Mg3 Sb2 phases are generated in the composites with the addition of Sb,and Mg3 Sb2 can refine obviously the coarse Mg2 Si phases by providing heterogeneous nuclei site.The morphological change in Mg2 Si particles occurs from coarse skeleton-like and petal-like to a small polygonal block shape with the increase of Sb content from 0.2%to 1.0%.The maximum size of Mg2 Si particles is decreased from 50μm to 8μm with adding 0.8% Sb.Meanwhile,the ultimate tensile strength,yield strength and elongation of the alloy reach 175.8 MPa,167.6 MPa and 1.67%,respectively.The tensile fracture of the alloy is characterized by quasi-cleavage at room temperature.