Analysis of semi-empirical interatomic potentials appropriate for simulation of crystalline and liquid Al and Cu
Analysis of semi-empirical interatomic potentials appropriate for simulation of crystalline and liquid Al and Cu
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DOI：
10.1080/14786430802206482
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发表时间：
2008-01-01
影响因子：
1.6
通讯作者：
Asta, M.
中科院分区：
文献类型：
--
作者：
Mendelev, M. I.;Kramer, M. J.;Asta, M.
研究了嵌入原子法（EAM）原子间相互作用势在深过冷熔体晶化动力学研究中的应用，重点研究了面心立方金属Al和Cu。对于这种应用，重要的是EAM电位准确地再现熔融性质和液体结构，以及最常适合其开发的结晶性质。为了测试以前公布的EAM潜力的准确性，并指导新的潜力在这项工作中的发展，第一性原理计算已进行和新的实验测量的Al和Cu的液体结构因子已进行了X射线衍射。我们证明，以前公布的EAM潜力预测液体结构，太强，相对于测量的衍射数据有序。我们开发了新的EAM势的Al和Cu，以提高与第一性原理和测量的液体衍射数据的协议。此外，我们计算液相扩散系数，并发现这个数量相关以及与液体结构。最后，我们进行分子动力学模拟晶体成核从熔体在淬火过程中在恒定的冷却速率。我们发现，EAM势，预测相同的零温晶体性质，但不同的液体结构，可以导致相当不同的结晶动力学。更有趣的是，我们发现，两个潜在的预测非常相似的平衡固体和液体的性质仍然可以产生非常不同的结晶动力学在远离平衡的条件下，这里采用的快速淬火模拟的特征。
We investigate the application of embedded atom method (EAM) interatomic potentials in the study of crystallization kinetics from deeply undercooled melts, focusing on the fcc metals Al and Cu. For this application, it is important that the EAM potential accurately reproduces melting properties and liquid structure, in addition to the crystalline properties most commonly fit in its development. To test the accuracy of previously published EAM potentials and to guide the development of new potential in this work, first-principles calculations have been performed and new experimental measurements of the Al and Cu liquid structure factors have been undertaken by X-ray diffraction. We demonstrate that the previously published EAM potentials predict a liquid structure that is too strongly ordered relative to measured diffraction data. We develop new EAM potentials for Al and Cu to improve the agreement with the first-principles and measured liquid diffraction data. Furthermore, we calculate liquid-phase diffusivities and find that this quantity correlates well with the liquid structure. Finally, we perform molecular dynamics simulations of crystal nucleation from the melt during quenching at constant cooling rate. We find that EAM potentials, which predict the same zero-temperature crystal properties but different liquid structures, can lead to quite different crystallization kinetics. More interestingly, we find that two potentials predicting very similar equilibrium solid and liquid properties can still produce very different crystallization kinetics under far-from-equilibrium conditions characteristic of the rapid quenching simulations employed here.