A Thermodynamic Description of the Gd-Mg-Y System
The thennodynamic modeling and optimization of the Gd-Mg, Mg-Y, Gd-Y binary systems and the Gd-Mg-Y ternary system were critically carried out by means of the CALPHAD (CALculation of PHAse Diagrams) technique. The solution phases (liquid, body-centered cubic, and 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, Mg5Gd, Mg3Gd, Mg2Gd and Mg24Y5 in the Gd-Mg-Y system were treated as the formulae (Mg, Y)2(Gd, Mg, Y), Mg5(Gd, Y), Mg3(Gd, Y), Mg2(Gd, Y) and Mg24(Gd, Mg, Y)4Y, respectively. A three-sublattice model (Gd, Mg, Y)0.5(Gd, Mg, Y)0.5(Va)3 is applied to describe the compound MgM formed by MgGd 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 Gd-Mg-Y system. A set of self-consistent thermodynamic description of the Gd-Mg-Y system was obtained. The projection of the liquidus surfaces for the Gd-Mg-Y system was constructed.Figs. 1-5 present the correlating phase diagram and properties diagram of the Mg-Y system calculated by present thermodynamic parameters with the experimental data. Figs. 6-8 show the calculated phase diagram and thennodynamic properties of Gd-Mg system by means of the thennodynamic parameters Fig. 9 shows the calculated phase diagram of the Gd-Y system with the thennodynamic parameters. Figs. 10-14 is the calculated isothermal section, isoplethic section and projection of the liquidus suefaces of the Gd-Mg-Y system, respectively.
Gd-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
103-106
2006-11-08（万方平台首次上网日期，不代表论文的发表时间）