Abstract The heating process for CuAlNi nanoclusters with cuboctahedral structure was studied by molecular dynamics simulation with the embedded atom method. A diffusionless martensitic transformation from the cuboctahedral (CO) to the icosahedral (ICO) structure before the melting point was found in some CuAlNi nanoclusters. The effects of element composition and cluster size on the thermodynamic stability and structural transformation of trimetallic nanoclusters were investigated. The results show that the CO–ICO transformation temperature was size-dependent and occurred only for small clusters. It was also observed that the CO–ICO transformation temperature firstly dropped and then raised as Al concentration increased, which may be strongly related to the release of excess energy. Furthermore, the surface segregation phenomenon was also observed that the lower surface energy components, such as Al and Cu atoms, segregated to the surface of CuAlNi nanoclusters. The changes in the melting points of CuAlNi nanoclusters with different alloy compositions and cluster sizes were also studied. And furthermore, the physical basis of structural transition of CuAlNi nanoclusters was discussed.

中文翻译：

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成分和尺寸对CuAlNi纳米团簇热力学稳定性和结构演变的影响

摘要 采用嵌入原子法通过分子动力学模拟研究了立方八面体结构的CuAlNi纳米团簇的加热过程。在一些 CuAlNi 纳米团簇中发现熔点之前从立方八面体 (CO) 到二十面体 (ICO) 结构的无扩散马氏体转变。研究了元素组成和团簇尺寸对三金属纳米团簇热力学稳定性和结构转变的影响。结果表明，CO-ICO 转变温度与尺寸有关，并且仅发生在小簇中。还观察到，随着铝浓度的增加，CO-ICO 转变温度先下降后升高，这可能与多余能量的释放密切相关。此外，还观察到表面偏析现象，较低的表面能成分，如 Al 和 Cu 原子，偏析到 CuAlNi 纳米团簇的表面。还研究了不同合金成分和团簇尺寸的CuAlNi纳米团簇熔点的变化。此外，讨论了CuAlNi纳米团簇结构转变的物理基础。