氦原子对镍金属中刃型位错运动行为影响的原子模拟

摘要

The molecular dynamics (MD) simulation and the modified analytical embedded-atom method (MAEAM) were used to study the influence of a He atom on the movement of the(a/2)〈110〉{111} edge dislocation in Ni. First, the calculated Burgers vector distribution shows that the equilibrium dissociation distance (Ded) and the stacking fault energy (Esf) between two partial edge dislocations are about 25.95 Å and 108 mJ/m2, respectively. Then, the obtained formation energies (Ef) of a He atom at some different sites demonstrate that the He atom is attracted and repelled in the tension and compression regions, respectively. And the He−dislocation interaction reveals that an interstitial He atom plays a more significant role in the dislocation movement than a substitutional He atom. Finally, it is found that the movement of an interstitial He atom is apparent as the first partial dislocation bypasses and the edge dislocation offers fast-diffusion path for the migration of a He atom.%应用分子动力学(MD)技术和改进分析型嵌入原子法(MAEAM)研究氦原子对镍金属中(a/2)〈110〉{111}刃型位错迁移行为的影响。首先通过计算晶格的Burgers矢量分布，确定两刃型分位错之间的平衡距离(Ded)约为25.95Å，而它们之间的堆垛层错能(Esf)约为108 mJ/m2。然后研究He原子在晶格中不同位置的形成能(Ef)，发现He原子在镍金属晶体的张力区域受到晶格的吸引，而其在压缩区域则受到晶格排斥。通过探讨 He 原子与刃型位错之间的相互作用发现，相比于置换He原子而言，间隙He原子对位错迁移行为的影响更强烈。最后，研究表明间隙He原子的迁移在第一个分位错跨过后表现更明显，同时刃型位错也为He原子迁移提供了更快速的扩散路径。