Sb对Mg-3Sn-1.5Al-1Zn-1.2Si合金组织性能的影响

摘要

在熔炼过程中以单质形式加入 Sb,研究了0~1.8%(质量分数,下同)范围内不同含量的 Sb 对Mg-3 Sn-1.5 Al-1 Zn-1.2 Si合金显微组织和力学性能的影响。结果表明,Sb 能与 Mg 基体优先生成 Mg3 Sb2相,加入1.0%的Sb 对Mg2 Si相的汉字状结构变质作用显著,Mg2 Si中的Si能与 Sn 发生取代反应,生成富Sn的Mg2(Si,Sn)。随着Sb 的增加,铸态合金和挤压态合金的延伸率逐渐减小,而抗拉强度呈现先增加后降低的趋势,塑性和强度的最佳配合点约为1.0%,Sb含量的增加有利于改善 Mg-3 Sn-1.5 Al-1 Zn-1.2 Si 合金的耐热性能。%The effects of Sb on microstructure and mechanical properties of Mg-3Sn-1.5Al-1Zn-1.2Si magnesium alloy were studied when Sb was added into melt in the form of pure metal with the range of 0-1 .8% (mass frac-tion,similarly hereinafter).The results demonstrate that Sb element and Mg matrix preferentially combine to form Mg3 Sb2 phases,the addition of 1 .0% Sb has a strong modification for Chinese script morphology Mg2 Si phases.Sn can replace Si of Mg2 Si then form Sn-rich Mg2 (Si,Sn)compound phase,whose physical properties lie between Mg2 Si and Mg2 Sn.With the increase of Sb content,the elongations of as-cast and extruded alloy decrease,and tensile strengths increase firstly and then decrease,a best combination of strength and plasticity was 1.0% or so.The increase of Sb was beneficial to improve the heat resistance of Mg-3Sn-1.5Al-1Zn-1.2Si alloy.