熔模精密铸造新型Mg-Zn-Al合金的显微组织及力学性能
Research on Microstructure and Mechanical Properties of New Mg-Zn-Al Alloy Prepared by Investment Casting
肖 伟1, 2, 梁松茂2, 赵忠兴1, 陈荣石2
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作者单位：(1. 沈阳理工大学 材料科学与工程学院, 辽宁 沈阳 110168; 2. 中国科学院金属研究所 金属腐蚀与防护国家重点实验室, 辽宁 沈阳 110016)
中文关键字：Mg-Zn-Al合金； 熔模铸造； 显微组织； 力学性能
英文关键字：Mg-Zn-Al alloy; investment casting; microstructure; mechanical properties
中文摘要：采用熔模精密铸造法制备了Mg-9wt%Zn-3wt%Al(简写为ZA93，下同)合金。利用扫描电镜，X - 射线衍射(XRD)，冷却曲线热分析技术(CA - CCA)研究了ZA93合金的显微组织和凝固路径。同时，研究了熔模铸造ZA93合金在铸态、T4(固溶处理)和T6(固溶 ＋ 时效处理)状态下的显微组织和力学性能。结果表明，ZA93合金在凝固过程中依次析出α- Mg相、准晶I相和共晶ε- MgZn相，对应温度分别为602、342和332 ℃；T6处理后，在合金晶内和晶界处析出细小强化相，提高了合金强度。
英文摘要：Mg-9wt%Zn-3wt%Al (ZA93) was prepared by investment casting. The microstructure characterization and the solidification pathway were investigated by SEM, EDS, XRD and computer aided-cooling curve analysis (CA-CCA). The effects of heat treatment on the microstructure and mechanical properties of ZA93 alloy were also investigated. The results show that quasi-crystalline I-phase and ε-MgZn phase are the main intermetallic phases in ZA93 alloy. During solidification, the solidification sequence of the second phase is α-Mg, quasi-crystalline I-phase and ε-MgZn phase, at 602 ℃, 342 ℃ and 332 ℃, respectively. Solid solution treatment followed by aging treatment (T6 treatment) significantly improves the tensile strength of the alloy due to the precipitation of some fine intermetallic particles along the grain boundaries