Molecular Dynamics Simulations of Solidification in Al-Si Alloys

铝硅是最受欢迎的铝铸造合金，用于生产航空航天和汽车应用的轻质部件。多年来，人们已经知道，在Al-Si中添加少量的某些杂质可以显著提高强度和韧性，但这些杂质在提高力学性能方面所起的确切作用还不完全清楚。在这项工作中，我们将首次利用计算机模拟来研究Al-Si合金在凝固过程中固-液界面上发生的原子水平过程。了解选择的杂质添加如何导致铸件结构的变化，将为改进合金的设计铺平道路。 研究中使用的技术是分子动力学，这是一种计算技术，它跟踪作为时间函数的每个原子在大系统中的位置。随着快速并行计算集群的出现，分子动力学模拟现在可以应用于由数百万个原子组成的固液系统。

Al-Si is the most popular Al cast alloy for the production of lightweight components for aerospace and automotive applications. It has been known for many years that small additions of certain impurities to Al-Si leads to significant improvements in strength and toughness, yet the precise role played by the impurities in enhancing mechanical properties is not completely understood. In this work we will utilize computer simulations to study, for the first time, the atomic level processes taking place at the solid-liquid interface during solidification in Al-Si alloys. An understanding of how select impurity additions lead to changes in the structure of the cast product will pave the way for the design of improved alloys. The technique employed in the study is molecular dynamics, a computational technique which tracks, as a function of time, the positions of each atom in a large system. With the advent of fast parallel computational clusters, molecular dynamics simulations applied to solid-liquid systems of millions of atoms can now be achieved.