摘要
针对镁稀土多元变合金相图的匮乏问题,对Mg-Gd-Y系合金进行了热力学模拟计算,分析了合金系的相组成和凝固过程,同时,通过SEM-EDS及XRD对所设计合金的微观组织和相组成进行验证。结果表明Mg-Gd-Y合金系主要由α（Mg）、Mg5Gd和Mg24Y5组成,且随着Y含量增加,Y固溶度增加,时效硬化效果提高,结晶温度间隔增大,使铸造性能降低;在Gd含量为1.8%~12.31%时,Mg-x Gd-4Y合金系的凝固顺序为：L→L＋α（Mg）→α（Mg）→α（Mg）＋Mg5Gd→α（Mg）＋Mg24Y5＋Mg5Gd,热处理强化区1.8%，
Aiming at the lack of phase diagram of magnesium rare earth multi variable alloy, the thermodynamic simulation calculation of Mg-Gd-Y alloy was carried out. The phase composition and solidification process of the alloy system were analyzed. Meanwhile, the microstructure and phase composition of the designed alloy was verified by SEM-EDS and XRD. The results show that Mg-Gd-Y alloy is mainly composed of ot（Mg）, Mg5Gd and Mg24Y5. With Y content increasing, the solid solubility of Y increases, so the age hardening effect elevates and crystallization temperature interval increases, which can make the casting property reduce. The order of solidification of Mg-xGd-4Y alloy is： L→L＋ α（Mg）→α（Mg）→α（Mg）＋Mg5Gd→α（Mg）＋Mg24Y5＋Mg5Gd under the Gd content of 1.8%-12.31%. The heat strengthened zone is 1.8%〈Gd%〈12.3 1%. Under the condition of non-equilibrium solidification, the composition of cast phase of Mg-Gd-Y alloy is α （Mg）, Mg5 （Gd,Y） and Mg24（Y,Gd）5. The atomic radius of Gd and Y is similar, so the two atoms change with each other.
出处
《热加工工艺》
CSCD
北大核心
2016年第12期37-40,共4页
Hot Working Technology
关键词
镁稀土合金
相图计算
凝固过程
相组成
Mg-RE alloy
phase diagram calculation
solidification
phase composition
