论文标题
使用群集扩展和统计力学对Al-CU相图的富含Al的部分预测
Prediction of the Al-rich part of the Al-Cu phase diagram using cluster expansion and statistical mechanics
论文作者
论文摘要
α-AL和其他相（GP区域，θ''，θ'和θ）的热力学特性通过统计机制结合使用群集扩展形式形式，并获得了Al-Cu系统的富集部分。该信息用于考虑θ'的振动熵贡献，以构建Al-Cu相模的富集部分，因为其他阶段的熵贡献可以忽略不计。 α-AL与θ''，θ'或θ相对温度的函数之间的相边界的模拟预测与实验数据非常吻合，并将相边界扩展到更大的温度范围。 DFT计算揭示了可能在低温下与α-al和θ''共存的许多亚稳态的吉尼更耐牙本区构型。他们还证明θ'是低于550k的稳定相，但由于振动熵对θ'的吉布斯能量的贡献，它被θ替换在该温度以上。这项工作表明了如何使用群集扩展和统计力学的组合来扩展我们对金属合金相位图的了解，并提供不同阶段的Gibbs自由能，这些阶段可以用作降水量表模拟中的输入。
The thermodynamic properties of α-Al and other phases (GP zones, θ'', θ' and θ) in the Al-rich part of the Al-Cu system have been obtained by means of the cluster expansion formalism in combination with statistical mechanics. This information was used to build the Al-rich part of the Al-Cu phase-diagram taking into account vibrational entropic contributions for θ', as those of the other phases were negligible. The simulation predictions of the phase boundaries between α-Al and either θ'', θ' or θ phases as a function of temperature are in good agreement with experimental data and extend the phase boundaries to a wider temperature range. The DFT calculations reveal the presence of a number of metastable Guinier-Preston-zone type configurations that may coexist with α-Al and θ'' at low temperatures. They also demonstrate that θ' is the stable phase below 550K but it is replaced by θ above this temperature due to the vibrational entropic contribution to the Gibbs energy of θ'. This work shows how the combination of cluster expansion and statistical mechanics can be used to expand our knowledge of the phase diagram of metallic alloys and to provide Gibbs free energies of different phases that can be used as input in mesoscale simulations of precipitation.
