基于原子-分子理论的二元合金熔体热力学计算

Thermodynamic calculating of binary alloy melts based on atom-molecule theory

分别使用Miedema、MIVM、NRTL、Wilson二元合金系热力学模型及Fact Sage热力学软件计算Bi-Pb、Bi-Sn、Cd-Pb、Pb-Sn 4个二元合金系的活度值,并与实验值进行比较.结果表明:Miedema、MIVM、NRTL、Wilson模型计算不同体系活度的效果不同,每种模型都有其适用的体系.而Fact Sage热力学软件计算的活度均与实验值吻合较好,文中使用Fact Sage分别计算Bi-Pb、Bi-Sn、Cd-Pb、Pb-Sn 4个二元系不同温度下的活度值.同时利用原子-分子理论计算Bi-Pb二元系质量作用浓度,给出生成金属间化合物Bi Pb反应的标准吉布斯自由能的表达式.

The activities in Bi-Pb, Bi-Sn, Cd-Pb, Pb-Sn binary alloy system were calculated by Miedema model, molecular interaction volume model （MIYM）, non -random two -liquid （NRTL） equation and thermodynamic modeling software FactSage respectively, and compared with measured value. The experimental results show that the Miedema model, MIYM model, NRTL model, Wilson model are not applicable to the above -mentioned four binary alloy system. But the measured activities has good corresponding with the calculated activities by thermodynamic modeling software FactSage, and the activities are calculated by using FactSage at different temperature. Meanwhile, a thermodynamic model for calculating the mass action concentration of structural units in Bi-Pb binary alloy system based on the atom-molecule coexistence theory has been developed, and the expression of standard Gibbs free energy change of reaction for forming intermetallic molecules as BiPb was put forward.