(东北大学 材料各向异性与织构教育部重点实验室，沈阳 110004)
摘 要: 采用合金法，利用XRD、SEM-EDS测定一系列Mg-Sn-Y三元合金在500 ℃下富Mg角处相平衡关系及各相平衡成分，建立Mg-Sn-Y三元系在500 ℃下富Mg角处的等温截面相图。结果表明：Mg-Sn-Y三元系富Mg角处存在Mg2Sn、MgSnY、Sn3Y5和Mg24+xY5 4种化合物与α-Mg固溶体平衡，从而构建3个三相区和4个两相区；Sn在α-Mg基体中的固溶度为2.5%~3.9%(摩尔分数)，Y在α-Mg基体中的固溶度为1.1%，但二者不能同时固溶到α-Mg基体中，同时Sn3Y5相中大约可以固溶3.6%~4.1%的金属Mg；由于MgSnY和Sn3Y5等一些高熔点化合物在高温下能够稳定存在，使得Mg-Sn-Y体系有可能成为一种潜在的新型耐热镁合金。
关键字: Mg-Sn-Y三元系；相平衡；等温截面；固溶度
Mg-Sn-Y ternary system at 500 ℃
（Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education,
Northeastern University, Shenyang 110004, China）
Abstract:By equilibrated alloy method the phase equilibria relation and phase equilibria composition of the Mg-riched corner in the Mg-Sn-Y ternary system at 500 ℃ were determined by XRD and SEM-EDS, thus the isothermal section of this ternary system was constructed. The results show that four intermetallic compounds exist in equilibrium with the α-Mg solid solution, i.e. Mg2Sn, MgSnY, Sn3Y5 and Mg24+xY5. Therefore, three three-phase regions and four two-phase regions are constructed. The solubility of Sn and Y in the α-Mg solid solution are 2.5%−3.9% and 1.1% (mole fraction), respectively, but they can not be simultaneously soluted in α-Mg solid solution. In addition, about 3.6%−4.1% Mg is detected in the Sn3Y5 phase. Due to high thermal stability of the compounds such as MgSnY and Sn3Y5, it is thus expected that the Mg-Sn-Y-based alloy could be a promising creep resistant alloy by appropriate alloy design and processing.
Key words: Mg-Sn-Y ternary system; phase equilibrium; isothermal section; solubility
