Abstract In this study, we computed the elastic properties of Cu-Zn binary intermetallic compounds, CuZn, Cu5Zn8 and CuZn4, by first-principles calculation and discussed the capability of the improvement in stiffness of aluminum alloys by aging treatment. The disordered CuZn4 with random atom distribution was emulated for the first time by virtual crystal approximation (VCA) model and special quasirandom structure (SQS) model with symmetry-based projection (SBP) technique. From the present calculation results, it was found that Young’s modulus of polycrystalline aggregate of CuZn4 is almost comparable to the highest counterpart of Cu5Zn8 with lower elastic anisotropy, but the expected volume fraction of CuZn4 is much higher than that of Cu5Zn8 after aging treatment. According to the rule of mixtures for the aluminum matrix and differently oriented intermetallic compounds, therefore, CuZn4 was rationally recommended as the most suitable intermetallic compound for improving the stiffness of Al-Cu-Zn alloys.

中文翻译：

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提高铝合金刚度的Cu-Zn金属间化合物弹性性能的第一性原理计算

摘要 在本研究中，我们通过第一性原理计算计算了Cu-Zn二元金属间化合物CuZn、Cu5Zn8和CuZn4的弹性性能，并讨论了时效处理提高铝合金刚度的能力。通过虚拟晶体近似（VCA）模型和基于对称投影（SBP）技术的特殊准随机结构（SQS）模型首次模拟了具有随机原子分布的无序CuZn4。从目前的计算结果可以发现，CuZn4 多晶骨料的杨氏模量几乎与弹性各向异性较低的最高对应物 Cu5Zn8 相当，但时效处理后 CuZn4 的预期体积分数远高于 Cu5Zn8。