Ca对铸态Mg-6Al及Mg-6Al-2Si系合金组织与性能的影响

摘要

To clarify the effects of alloying element Ca on properties of Mg-6Al-0.3Mn-0.5Zn-1.5Sn-0.3Sr-xCa (x =0,0.5%) and Mg-6Al-2Si-0.3Mn-0.5Zn-1.5Sn-0.3Sr-%Ca(x=0, 0.5%) alloys at different working temperature, the phase constituent, microstructure, fracture morphologies and tensile properties at room temperature and 150 °C were investigated by X-ray diffraction, optical microscopy, scanning electron microscopy and mechanical test machine.The results show that Ca addition can cause the formation of CaMgSn, CaMg (Sn, Si) and other second phases, lead to the obvious solid solution strengthening, increase the tensile strength at room and high temperature.Si addition can improve the tensile strength at high temperature but decrease that at room temperature.Therefore, Mg-6Al-0.3Mn-0.5Zn-l.5Sn-0.3Sr-0.5Ca is suitable for room temperature parts, while Mg-6Al-2Si-0.3Mn-0.5Zn-1.5 Sn-0.3 Sr-0.5Ca is suitable for higher temperature parts.%为了明确不同服役温度下Ca对Mg-Al和Mg-Al-Si系合金性能的影响,采用X射线衍射仪、光学显微镜、扫描电镜和力学性能试验机,分别研究了Mg-6Al-0.3Mn-0.5Zn-1.5Sn-0.3Sr-xCa(x=0,0.5％)和Mg-6Al-2Si-0.3Mn-0.5Zn-1.5Sn-0.3Sr-xCa (x=0,0.5％)合金的相组成、显微组织、断口形貌,以及室温和150℃时的拉伸性能.结果表明,Ca的加入会促使CaMgSn和CaMg (Sn,Si)等第二相的生成,产生明显的固溶强化作用,提高合金的室温和高温拉伸性能.Si的加入可显著提高合金的高温性能,但会降低合金的室温性能.因此,Mg-6A1-0.3Mn-0.5Zn-1.5Sn-0.3Sr-0.5Ca合金适用于室温部件,而Mg-6Al-2Si-0.3Mn-0.5Zn-1.5Sn-0.3Sr-0.5Ca合金适用于高温部件.