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运用Miedema混合焓模型计算了Al-Er、Si-Er和Al-Si二元合金的部分热力学性质,选择Er为非对称性组元,在此基础上结合Toop模型计算出Al-Si-Er三元合金的混合焓、过剩熵与过剩自由能。结果表明,Al-Si-Er三元合金的混合焓、过剩熵与过剩自由能在整个浓度范围内均为负值,在富Er和贫Er区域各热力学参数变化趋势较大。通过计算Al、Si和Er3种组元的偏摩尔过剩自由能得到Al-Si-Er三元合金各组元的等活度值曲线。曲线显示各组元随着摩尔分数的减少其活度值都急剧减小,在三元系成分三角形的中心部分Al、Si和Er的活度值都很小,这表明Al、Si和Er3种组元之间存在很强的相互作用,易形成三元金属间化合物,这一结论与Al-Si-Er三元相图的实际情况相符合。
The partial thermodynamic properties of Al-Er, Si-Er and Al-Si binary alloys were calculated by Miedema mixed enthalpy model, and Er was selected as the asymmetric component. Based on this, combined with the Toop model, the Al-Si- Metallurgy enthalpy of mixing, excess entropy and excess free energy. The results show that the enthalpy of fusion, excess entropy and excess free energy of Al-Si-Er ternary alloy are all negative in the whole concentration range, and the thermodynamic parameters of Al-Si-Er ternary alloy show a large variation trend in Er-rich and Er-depleted regions. By calculating the excess partial excess free energy of Al, Si and Er three kinds of components, the isosurface value curves of Al-Si-Er ternary alloy were obtained. The curves show that the activity values of each component decrease sharply with the decrease of the molar fraction, and the activity values of Al, Si and Er in the central part of the ternary component triangle are very small, indicating that Al, Si and Er3 species Strong interaction between the components, easy to form ternary intermetallic compounds, this conclusion is consistent with the actual situation Al-Si-Er ternary phase diagram.