Al-Zr,Al-Y和Zr-Y二元合金熔体热力学性质的计算

Calculation of thermodynamic properties of Al-Zr,Al-Y and Zr-Y binary alloy melts

基于Miedema模型,利用热力学基本原理及元素的基本性质,计算Al-Zr,Al-Y和Zr-Y二元系统的混合焓、过剩熵、过剩吉布斯自由能以及各组元的活度。基于Al-Zr和Al-Y二元合金相图的数据,计算Al3Zr和Al3Y相析出反应的吉布斯自由能。研究结果表明:Al-Zr和Al-Y二元合金熔体的混合焓、过剩熵和过剩吉布斯自由能都小于0 J,各组元的活度相对于理想溶液发生了较大的负偏差,而Zr-Y二元合金熔体的混合焓、过剩熵和过剩吉布斯自由能大于0 J,各组元的活度相对于理想溶液发生了较大的正偏差,说明Al与Zr和Y原子有较强的相互作用,而Zr和Y原子相互作用不大。2种相析出反应的吉布斯自由能都小于0 J,且Al3Y相的吉布斯自由能更小,表明过渡族元素Zr和稀土元素Y同时加入到纯Al时,更容易生成Al3Y;计算结果和实验结果相吻合,证明Miedema模型的合理性。

Based on the Miedema model, the enthalpies of formation, excess entropies, excess Gibbs free-energy and the activity among all components of Al-Zr,Al-Y and Zr-Y binary systems were calculated using the basic thermodynamics principle and basic properties of the element. According to the phase diagrams of Al-Zr and Al-Y binary alloy, the Gibbs free-energy of the phase precipitation reaction of Al3Zr and A13Y were deduced. The results show that the values of Al-Zr and Al-Y binary alloy melts are all negative. The activity presents a larger negative bias compared with the ideal solution. In contrast, the values of Zr-Y binary alloy melt are all positive. Compared to the ideal solution, the activity has a larger positive bias, which indicates that A1 has stronger interaction with Zr and Y, whereas, there is a weaker interaction force between Zr and Y atoms. Gibbs free-energy of Al3Zr and Al3Y are all negative and that of Al3Y is lower, so when the transition metal Zr and the rare earth Y are added to A1 at the same time, Al3Y forms prior to Al3Zr. The rationality of Miedema model is demonstrated, and the calculated data are good agreement with the experimental data.