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| 外应力场下NiAl合金微裂纹动态扩展的分子动力学模拟 |
| Molecular Dynamics Simulation of Micro-crack Propagation in NiAl Alloy under External Stress Field |
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| DOI：10.3969/j.issn.1674-6457.2022.07.021 |
| 中文关键词: NiAl材料 形变 断裂 位错 分子动力学 |
| 英文关键词: NiAl material deformation fracture dislocation MD |
| 基金项目: |
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| 中文摘要: |
| 目的 对NiAl合金中不同晶体取向的裂纹扩展动力学行为进行原子尺度研究，明晰在塑性变形过程 |
| 英文摘要: |
| The work aims to study the crack propagation dynamics behavior in NiAl alloy with various crystal orientations at atomic scale, clarify the brittle cleavage and deformation behavior of crack tip during plastic deformation or practical engineering application and provide a theoretical basis for the study of plastic deformation behavior and service life evaluation of NiAl alloy. In this paper, four crack tip models with different orientations were established, which were (010)[001], (01) [100], (010)[101] and (01)[011], respectively. The above models were simulated by molecular dynamics method. Gear algorithm was adopted to calculate the motion of atoms under real stress state. The results showed that the crack tip reaction of micro-cracks in NiAl alloy under external loading was strongly dependent on the crack orientation (crack surface and crack front direction). The crack model of {110} crack plane was prone to brittle cleavage propagation. The crack configuration of {100} crack surface had a certain plasticity. Dislocated emission and coordinated plastic deformation could be formed at the crack tip. The simulation results were consistent with the experimental observations in literature. The crystal orientation of the crack has an important effect on the martensite transformation behavior at the crack tip. When the crack front is <100>, the atoms move on the {100} slip plane at the crack front, inducing the transformation of B2 into L10, and thus producing martensite transformation, which is beneficial to the effect of phase transformation and toughness, and can promote the dislocated emission at the crack tip, and is beneficial to improve plasticity and service life of NiAl material. |
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