摘要
Mg-xGd-0.6Zr （x=2, 4, 6, mass fraction） alloys were prepared by semi-continuous casting process. The effects of Gd content on the microstructures and mechanical properties of Mg-xGd-0.6Zr alloys were studied and the solid solution treatment process of Mg-6Gd-0.6Zr alloys was optimized. The microstructures and mechanical properties of all the studied alloys were analyzed by optical microscope, X-ray diffraction, scanning electron microscope equipped with energy dispersive spectroscope and micro-hardness tester. The results show that the grain size slightly decreases with increasing Gd content and there is a close linear relationship between Gd content and micro-hardness of Mg-xGd-0.6Zr alloys. The second phases Mg 2 Gd and Mg 3 Gd formed due to non-equilibrium solidification during the casting process can be transformed into equilibrium phase Mg 5.05 Gd which can dissolve into α-Mg solid solution phase at solution temperature of 460 ℃ The optimized solid solution treatment of Mg-6Gd-0.6Zr alloy is （300 ℃ 6 h） ＋ （460 ℃ 10 h）.
使用半连续铸造法制备Mg-xGd-0.6Zr(x=2, 4, 6, 质量分数) 镁合金,研究不同Gd含量对Mg-xGd-0.6Zr合金组织与力学性能的影响,优化 Mg-6Gd-0.6Zr 合金的固溶处理工艺。采用光学显微镜、X 射线衍射仪、扫描电子显微镜、能谱仪和显微硬度仪对合金的组织和力学性能进行表征。结果表明,随着合金中Gd含量的增加,晶粒尺寸略减小;Mg-xGd-0.6Zr 合金的显微硬度与Gd的摩尔浓度呈线性关系。在铸造过程中由非平衡凝固形成的 Mg2Gd 和 Mg3Gd 在固溶处理时将转变成Mg5.05Gd平衡相;当固溶温度超过 460 °C时,Mg5.05Gd 溶解到α-Mg中。Mg-6Gd-0.6Zr合金的优化固溶处理工艺为(300 °C, 6 h) + (460 °C, 10 h)。
基金
Project(50725413)supported by the National Natural Science Foundation of China
Project(CDJZR10130020)supported by the Fundamental Research Funds for the Central Universities, China
