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基于位错理论，利用分子动力学方法建立了〈100〉010，〈100〉011，1/2〈111〉011和1/2〈111〉112刃型位错的芯结构，并计算了这四种刃型位错的形成能、位错芯能量和芯半径.计算结果表明：〈100〉010和〈100〉011刃型位错的形成能比1/2〈111〉011和1/2〈111〉112刃型位错的要高，这表明〈100〉刃型位错比1/2〈111〉刃型位错更难形成.而〈100〉010和〈100〉011刃型位错的芯半径比1/2〈111〉011和1/2〈111〉112刃型位错的小，这说明在1/2〈111〉刃型位错中位于奇异区的原子数多于〈100〉刃型位错，而这些原子要比完整晶体中的原子具有更大的活性.可见，1/2〈111〉刃型位错比〈100〉刃型位错更易运动，且〈100〉刃型位错在bcc Fe中难以形成.Based on the theory of dislocations, we have constructed the four models of the 〈100〉010, 〈100〉011, 1/2〈111〉011 and 1/2〈111〉112 edge dislocations in bcc Fe using the molecular dynamics method, and the formation energy, core energy and core radius of the dislocations have been calculated respectively. The calculated results indicated that the formation energies of 〈100〉010 and 〈100〉011 edge dislocations are higher than those of 1/2〈111〉011 and 1/2〈111〉112 edge dislocations. This shows that the formation of 1/2〈111〉 edge dislocation is easier than that of 〈100〉 edge dislocation. However, the core radii of 〈100〉010 and 〈100〉011 edge dislocations are smaller than those of 1/2〈111〉011 and 1/2〈111〉112 edge dislocations. This shows that the atomic numbers locating at the singular region in the 1/2〈111〉 edge dislocation are greater than those in 〈100〉 edge dislocation. Therefore, the motion of 1/2〈111〉 edge dislocation is easier than that of 〈100〉 edge dislocation.
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Keywords:
- bcc Fe /
- edge dislocation /
- molecular dynamics simulation
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中国物理学会期刊
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