铜、铝、镍原子间相互作用势对弹性性能预测的评价
Evaluation of Copper, Aluminum and Nickel Interatomic Potentials on Predicting the Elastic Properties
摘要：
选择合适的力场是任何原子模拟的主要问题之一，需要认真考虑，以产生可靠的结果。由于在微米/纳米材料的力学行为的调查已经变得越来越普遍，它是必要的，以确定一个足够的潜力，准确地模拟所需的应用程序的原子的相互作用。在此框架下，研究了基于多嵌入原子方法的原子间相互作用势预测弹性性能的可靠性。在室温下对不同的铜、铝和镍原子间相互作用势进行了评估，这被认为是最适用的情况。这三个物种的力场来自美国国家标准与技术研究所（NIST）的在线存储库，以及桑迪亚国家实验室的LAMMPS数据库。采用分子动力学模拟方法，得到了Cu、Al和Ni立方单晶的三个独立的弹性常数C11、C12和C44。Voigt-Reuss-Hill近似将单晶体的弹性常数转化为各向同性的多晶体的弹性模量，包括体模量、剪切模量、杨氏模量和泊松比。大规模分子动力学的模拟结果与文献中的实验数据进行了比较，以证明每个物种的每个潜在的鲁棒性。最后，精确的原子间相互作用势被推荐用于寻找纯物质的每一种弹性性质。研究发现，弹性性质的精确性对力场的选择很敏感。这些电位适合于特定的化合物可能不一定对所有现有的纯物质都准确。
英文摘要：
Choice of appropriate force field is one of the main concerns of any atomistic simulation that needs to be seriously considered in order to yield reliable results. Since, investigations on mechanical behavior of materials at micro/nanoscale has been becoming much more widespread, it is necessary to determine an adequate potential which accurately models the interaction of the atoms for desired applications. In this framework, reliability of multiple embedded atom method based interatomic potentials for predicting the elastic properties was investigated. Assessments were carried out for different copper, aluminum and nickel interatomic potentials at room temperature which is considered as the most applicable case. Examined force fields for the three species were taken from online repositories of National Institute of Standards and Technology (NIST), as well as the Sandia National Laboratories, the LAMMPS database. Using molecular dynamic simulations, the three independent elastic constants, C11, C12 and C44 were found for Cu, Al and Ni cubic single crystals. Voigt-Reuss-Hill approximation was then implemented to convert elastic constants of the single crystals into isotropic polycrystalline elastic moduli including Bulk, Shear and Young's modulus as well as Poisson's ratio. Simulation results from massive molecular dynamic were compared with available experimental data in the literature to justify the robustness of each potential for each species. Eventually, accurate interatomic potentials have been recommended for finding each of the elastic properties of the pure species. Exactitude of the elastic properties was found to be sensitive to the choice of the force fields. Those potentials were fitted for a specific compound may not necessarily work accurately for all the existing pure species.
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