Zhao Hao, Bresme Fernando
Department of Chemistry, Molecular Sciences Research Hub, Imperial College, London W12 0BZ, U.K.
State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China.
J Chem Theory Comput. 2024 Sep 5;20(18):8190-201. doi: 10.1021/acs.jctc.4c00628.
Alumina and aluminum are strategic materials employed in energy applications, with metal aluminum being interesting in phase change material applications. Therefore, the theoretical description of the thermophysical properties of these materials represents an important objective. Here, we investigate the liquid-solid coexistence properties of aluminum and alumina using a state-of-the-art reactive force field (ReaxFF) and molecular dynamics simulations. Aluminum features ultrafast crystal growth, which enables the direct determination of its melting temperature via direct coexistence simulations (858 ± 2 K). However, at standard pressure, alumina is easily trapped in a glass state, preventing the application of the direct coexistence method. We demonstrate that direct coexistence can be used at high pressures above 2 GPa, where alumina features a higher melting temperature, and the liquid-solid interface exhibits enhanced dynamics. Our approach opens a route to obtain the melting temperature of ReaxFF alumina at standard pressure (1670 ± 10 K) and, more generally, a viable method for calculating the melting point of metal oxides via direct coexistence simulations. We further investigated the dynamics of crystal growth of the solid-liquid aluminum and alumina interfaces.
氧化铝和铝是能源应用中使用的战略材料，金属铝在相变材料应用中很受关注。因此，对这些材料热物理性质的理论描述是一个重要目标。在此，我们使用最先进的反应力场（ReaxFF）和分子动力学模拟来研究铝和氧化铝的液固共存性质。铝具有超快的晶体生长特性，这使得通过直接共存模拟能够直接确定其熔化温度（858 ± 2 K）。然而，在标准压力下，氧化铝很容易被困在玻璃态，这使得直接共存方法无法应用。我们证明，在高于2 GPa的高压下可以使用直接共存方法，此时氧化铝具有更高的熔化温度，并且液固界面表现出增强的动力学特性。我们的方法开辟了一条途径，可获得标准压力下ReaxFF氧化铝的熔化温度（1670 ± 10 K），更普遍地说，是一种通过直接共存模拟计算金属氧化物熔点的可行方法。我们还进一步研究了固液铝和氧化铝界面的晶体生长动力学。
