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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25.95?,而它们之间的堆垛层错能(Esf)约为108 m J/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。
The molecular dynamics (MD) technique and the modified analytic embedded atom method (MAEAM) were used to study the effect of helium atom on the dislocation mobility of (110) {111} edge in (a / 2) Firstly, the Burgers vector distribution of the lattice is calculated, and the equilibrium distance (Ded) between two-edge dislocations is determined to be about 25.95 ?, and the stacking fault energy (Esf) between them is about 108 mJ / m2 . Then the formation energy (Ef) of He atoms at different positions in the lattice is studied. It is found that the He atoms are attracted by the lattice in the tension region of the nickel metal crystal and are lattice-repulsive in the compression region. By investigating the interaction between He atoms and edge-type dislocations, it is found that the interstitial He atoms have a stronger influence on the dislocation migration than the He atoms. Finally, studies show that the migration of interstitial He atoms is more pronounced after the first dislocations cross, and edge dislocations also provide a faster diffusion path for He atom migration.