Thermodynamic Optimization of the La-Mg-Y System
The thermodynamic modeling and optimization of the La-Mg, La-Y binary systems and the La-Mg-Y ternary system were critically carried out by means of the CALPHAD (CALculation of PHAse Diagram) technique. The solution phases (liquid, body-centered cubic, face-centered cubic, hexagonal close-packed and double hexagonal close-packed) were modeled with the Redlich-Kister equation. The Compound Energy Model has been used to describe the thermodynamic functions of the intermetallic compounds in these systems. The compounds Mg2Y, Mg12La, Mg17La2, Mg41La5, Mg3La, Mg2La and Mg24Y5 in the La-Mg-Y system were treated as the formulae (Mg,Y)2(La,Mg,Y), Mg12(La,Y), Mgl7(La,Y)2, Mg41(La,Y)5, Mg3(La,Mg,Y), Mg2(La,Y) and Mg24(La,Mg,Y)4Y, respectively. A model (La,Mg,Y)0.5(La,Mg,Y)0.5Va3 is applied to describe the compound MgM formed by MgLa and MgY in order to cope with the order-disorder transition between body-centered cubic solution (A2) and MgM with CsCl-type structure (B2) in the La-Mg-Y system. A set of self-consistent thermodynamic description of the La-Mg-Y system was obtained. The projection of the liquidus surfaces and the entire reaction scheme for the La-Mg-Y system were predicted and constructed.
La-Mg-Y system Thermodynamic modeling Order-disorder transition Rare earth alloys CALPHAD technique
Cuiping Guo Zhenmin Du Changrong Li
Department of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
国际会议
厦门
英文
99-102
2006-11-08（万方平台首次上网日期，不代表论文的发表时间）