Si-Ca-Ba三元合金熔体热力学性质的计算

根据Miedema二元合金生成热模型和Toop非对称几何模型,对1 873 K时Si-Ca-Ba三元合金熔体过剩自由能、生成热、过剩熵以及各组元间的活度交互作用系数等热力学性质进行了计算.结果表明,在1 873 K时Si-Ca-Ba合金熔体的过剩自由能、生成热和过剩熵均为负值.在富硅区域和硅含量较少的区域,各热力学性质的变化趋势较大.过剩自由能、生成热和过剩熵的最小值均出现在xSi=55%,xCa=45%,xBa=0成分处.Si-Ca-Ba合金中组元钡的加入,对合金的过剩自由能、生成热和过剩熵影响不大,随钡含量的增加,各热力学性质无显著变化.

Calculating Thermodynamic Properties of Si-Ca-Ba Ternary Alloy Melts

Based on the Miedema formation heat model for binary alloy and the Toop asymmetric geometrical model,the excess free energy,formation heat,excess entropy and the interactive coefficients of activity among all components of Si-Ca-Ba ternary alloy melts were calculated thermodynamically at 1 873 K.The results showed that their values are all negative,and the thermodynamic properties of the ternary alloy tend to change obviously in the zone where the Si content is high or low.The minimum values of excess free energy,formation heat and excess entropy are all found at the point where the composition shows x(Si)=55%,x(Ca)=45% and x(Ba)=0.Adding barium to Si-Ca-Ba alloy melt does not affect obviously the excess free energy,formation heat and excess entropy,and such thermodynamic properties don't change greatly with the increasing addition of barium.