单晶Al0.1CoCrFeNi高熵合金裂纹扩展的分子动力学模拟

Molecular Dynamics Simulation of Crack Growth in Single Crystal Al0.1CoCrFeNi High Entropy Alloy

为了探究Al0.1CoCrFeNi高熵合金裂纹扩展机理,采用分子动力学方法对单晶Al0.1CoCrFeNi高熵合金中预制裂纹的扩展拉伸过程进行模拟及分析,研究在恒定温度下应变率对单晶Al0.1CoCrFeNi高熵合金裂纹扩展的影响。研究结果表明:室温下单晶Al0.1CoCrFeNi高熵合金呈韧性断裂,裂纹在扩展过程中发射位错并且裂纹尖端钝化;随着应变率的升高,裂纹扩展速度增加,合金位错密度强度增大,变形强度提高,材料塑形强度增加;裂纹尖端发射的位错堆积在边界附近,随着拉伸的继续,使得位错堆积处出现边界开裂的现象。

The paper aims to explore the mechanism of crack propagation in Al0.1CoCrFeNi high-entropy alloys.The molecular dynamics method was used to simulate and analyze the growth process of the precracks in single crystal of Al0.1CoCrFeNi high-entropy alloys,and the effect of the loading rate on the crack propagation in Al0.1CoCrFeNi high-entropy alloys at constant temperature was studied.The results show that the single crystal Al0.1CoCrFeNi high-entropy alloy exhibits ductile fracture at room temperature and that the dislocations are emitted during the crack propagation with passivated crack tips.As the loading rate increases,the crack propagation speeds up,the dislocation density and strength increase,the deformation strengthens and the plastic strength increases.Dislocations emitted from the crack tips accumulate near the boundary.As the extension continues,the boundary cracking happens where the dislocations accumulated.