论文标题
晶界隔离与晶界合金中的晶界扩散之间的关系
Relationship between grain boundary segregation and grain boundary diffusion in Cu-Ag alloys
论文作者
论文摘要
众所周知，合金成分可以分离为晶界（GBS），并且GBS中的原子迁移率大大超过了晶格中的原子迁移率，但对GB分离对GB扩散的影响知之甚少。原子计算机仿真提供了一种通过计算合金组件的GB扩散系数来获得隔离扩散关系的一种方法，该系数是其隔离量的函数。在此类模拟中，热力学平衡的GB分离是通过半宏观的蒙特卡洛方法制备的，然后通过分子动力学计算所有合金组件的扩散系数。作为演示，提出的方法应用于GB是CU-AG系统。获得的GB扩散率表现出非平凡的组成依赖性，可以通过站点阻塞，现场竞争以及由于预言效应而导致的GB无序发作。
While it is known that alloy components can segregate to grain boundaries (GBs), and that the atomic mobility in GBs greatly exceeds the atomic mobility in the lattice, little is known about the effect of GB segregation on GB diffusion. Atomistic computer simulations offer a means of gaining insights into the segregation-diffusion relationship by computing the GB diffusion coefficients of the alloy components as a function of their segregated amounts. In such simulations, thermodynamically equilibrium GB segregation is prepared by a semi-grand canonical Monte Carlo method, followed by calculation of the diffusion coefficients of all alloy components by molecular dynamics. As a demonstration, the proposed methodology is applied to a GB is the Cu-Ag system. The GB diffusivities obtained exhibit non-trivial composition dependencies that can be explained by site blocking, site competition, and the onset of GB disordering due to the premelting effect.
