Department of Physics, East China Normal University, Shanghai, 200062, China.
Physical Science and Technology College, Yangzhou University, Yangzhou, 225002, China.
Sci Rep. 2017 Aug 31;7(1):10241. doi: 10.1038/s41598-017-10662-x.
In order to understand the defect trapping during solidification in pure elements, we have performed molecular dynamics simulations on both aluminum and nickel. We find that vacancies are the dominant defects in the product crystals for both metals. For slight undercooling, the vacancy concentration strongly depends on the growth velocity, rather than the growth orientations, and there is an approximately linear relationship between the growth velocity and vacancy concentration. However, for deep undercooling, the vacancy concentration shows a remarkable anisotropy between (100) and (110) orientations. Based on the competition between atomic diffusion and growth, a possible mechanism for vacancy trapping is suggested.
为了理解纯元素凝固过程中的缺陷捕获，我们对铝和镍进行了分子动力学模拟。我们发现空位是这两种金属产物晶体中的主要缺陷。对于轻微的过冷度，空位浓度强烈依赖于生长速度，而不是生长方向，并且生长速度和空位浓度之间存在近似的线性关系。然而，对于深过冷度，空位浓度在（100）和（110）方向之间表现出显著的各向异性。基于原子扩散和生长之间的竞争，提出了一种空位捕获的可能机制。
