Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1635472 | Rare Metals | 2006 | 9 Pages |
Abstract
As an example of the La-Mg-Y system, the method how to set up the thermodynamic model of individual phases was introduced in the process of thermodynamic optimization. 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 the La-Mg-Y systems. The compounds Mg2Y, Mg24Y5, Mg12La, Mg17La2, Mg41La5, Mg3La and Mg2La in the La-Mg-Y system were treated as the formulae (Mg, Y)2(La, Mg, Y), Mg24(La,Mg,Y)4Y, Mg12(La,Y), Mg17(La,Y)2, Mg41(La,Y)5, Mg3(La,Mg,Y) and Mg2(La, Y), respectively. A model (La,Mg,Y)0.5(La,Mg,Y)0.5 was 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. The Gibbs energies of individual phases were optimized in the La-Mg, La-Y and La-Mg-Y systems by CALPHAD technique. The projection of the liquidus surfaces for the La-Mg-Y system was predicted. The Mg-based alloys database including 36 binary and 15 ternary systems formed by Mg, Al, Cu, Ni, Mn, Zn and rare earth elements was set up in SGTE standard.
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
DU Zhenmin, GUO Cuiping, LI Changrong, ZHANG Weijing,