稀土元素Gd和Sm对AZ81镁合金组织及力学性能的影响

Effect of Gd and Sm on the Microstructure and Mechanical Properties of AZ81 Magnesium Alloy

利用气体保护下感应熔炼方法制备了AZ81＋（Gd＋Sm）合金,采用光学金相（OM）、扫描电镜（SEM）、X射线衍射分析（XRD）、能谱分析（EDX）和拉伸性能测试等手段,对合金进行了显微组织、力学性能以及断口形貌分析。研究表明：Gd和Sm的添加使得合金晶粒得到细化,在稀土总含量为2%时细化效果最为明显,基体中形成了稀土-铝化合物Al2Sm和Al2Gd10随着Sm和Gd含量的增加,AZ81合金的室温和高温下的抗拉强度先升高后降低,稀土添加量在2%-3%时取得最好的强化效果,过量稀土恶化了组织,降低了性能。

The AZ81 magnesium alloys with Gd induction melting with gas protection method. The and Sm addition were prepared by medium-frequency influence of Gd and Sm addition on microstructure and properties of AZ81 alloys was investigated. The microstructure and mechanical properties of the alloys were researched by OM, SEM, XRD, EDS and tensile test. The results show that the microstructure is obviously refined with the addition of Gd and Sm. When the RE content is 2%, AZ81 alloy exhibits best refine effect. With the increase of Sm and Gd, the tensile strength of alloys at room temperature and high temperature firstly increases, and then decreases. When the addition amount is in the range of 2%-3%, the alloy exhibits best strengthening effect. And the excess addition of rare elements can worse the microstructure and weaken the strengthening effect of Mg-6Al alloy.