La-Mg-Ni体系富镁角的热力学优化与计算

Thermodynamic Assessment for the Mg-Rich Corner of the La-Mg-Ni System

运用CALPHAD方法系统地对La-Mg-Ni三元体系富镁角进行热力学优化与计算。选取置换溶液模型描述液相,三亚点阵模型描述La2Mg17-xNix,定化学计量比化合物模型描述LaMg2Ni,最终获得一组具有良好自恰性的热力学模型与参数。通过相图软件Pandat计算获得该区域的液相投影面图、673和773K下的等温截面相图以及平衡反应等,且计算得到的相图和热力学数据与试验数据较好地吻合。

A systematic thermodynamic description for the Mg-rich corner of La-Mg-Ni ternary system has been obtained using the CALPHAD approach. The substitutional solution model, the three-sublattice model and the stoichiometric compound model were used to describe the liquid, La2Mg17-xNix and LaMg2Ni phases, respectively. The model parameters were then optimized using the experimental information. Calculations were compared with the experimental data for the enthalpy of mixing in liquid, isothermal sections at 673 and 773 K, invariant reactions and partial liquidus surface. The calculation and the experimental data are in good agreement.