Si含量对Mg-5Sn-1.5Al-1.2Zn合金组织性能的影响

摘要

在熔炼过程中以镁硅中间合金形式加入Si元素,研究了0～1.6％范围内不同Si含量对Mg-5Sn-1.5Al-1.2Zn镁合金铸态组织及力学性能的影响.结果表明:合金元素Si与Mg基体结合生成了强化相Mg2Si,并在该相周围有Mg2(Si,Sn)复合相产生,Mg2(Si,Sn)相的出现对A1、Zn元素形成T-Mg32(Al,Zn)49相有促进作用；Si元素在0～1.6％变化时,试样合金的抗拉强度、伸长率呈现先升高后降低的趋势,当Si含量为1.0％时强度、塑性出现较佳配合,而合金的硬度则呈现持续增加,Si含量1.2％～1.6％范围内,硬度上升趋势变缓.%The effects of silicon content on as-cast microstructure and mechanical properties of Mg-5Sn-1. 5Al-12Zn magnesium alloy were studied when silicon element was added into melt in the form of magnesium-silicon interalloy with the range of 0-1.6%. The results indicate that Mg2Si is the strengthening phase made by combining alloying element silicon and magnesium matrix, and around Mg2Si phase Mg2(Si, Sn) composition is found, the emerging of Mg2(Si, Sn) advances the forming of τ-Mg32(Al, Zn)49 that is produced by Al and Zn elements. When Si element changes from 0 to 1.6%, tensile strength and elongation of the alloy display a trend which increase firstly and then decrease, its tensile strength and elongation match better when Si content is 1.0%, while hardness of the alloy is improved in the range of 0-1.6%Si, the increment of hardness becomes slow as Si content in the range of 1.2%-1.6%.