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常规镁合金晶粒粗大、高温力学性能低、耐蚀性差,限制了其在生产中的应用。添加变质剂以细化晶粒可提高其综合力学性能。采用“对渗法”制备不同成分配比Mg-Sr-Y合金,用光学金相显微镜、扫描电镜、能谱仪和XRD等研究了Sr/Y比值对Mg-Sr-Y合金组织形态及其第二相的影响。结果表明:Mg-Sr-Y合金组织由枝晶状的初生相α-Mg和鱼骨状的共晶组织(α-Mg+Mg17Sr2)及(α-Mg+Mg24Sr5)组成。实验随Y含量的增加,镁合金铸态组织得到细化,但Sr含量的增加却使合金组织粗化。
Conventional magnesium alloy coarse grains, high temperature mechanical properties, corrosion resistance is poor, limiting its application in the production. Adding modifier to refine grains can improve its comprehensive mechanical properties. The Mg-Sr-Y alloy with different compositions was prepared by “infiltration method”. The effects of Sr / Y ratio on the microstructure of Mg-Sr-Y alloy were studied by optical microscope, scanning electron microscope, And its second phase. The results show that the microstructure of Mg-Sr-Y alloy consists of dendritic primary phase α-Mg and fishbone eutectic (α-Mg + Mg17Sr2) and (α-Mg + Mg24Sr5). With the increase of Y content, the as-cast microstructure of magnesium alloy is refined, but the increase of Sr content causes the microstructure of the alloy to be coarsened.