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采用分子动力学方法对深冷环境下(77K)的单晶钛内诱导的位错扩展进行了模拟,使用共同近邻分析(CNA)法分析了温度对位错扩展的影响,系统研究了激光冲击波在深冷环境和常温环境条件下沿[0001]方向的冲击传播特性。结果表明,[0001]方向上单晶钛的激光冲击波为弹塑性双波结构。深冷环境下激光冲击波后材料内部出现大量位错,塑性变形主要表现为不全位错的发射和传播。冲击应力和剪切应力与激光冲击波速度呈线性关系。深冷环境下的激光冲击波速度与冲击波压力均高于常温下的,冲击波速度提高了9%~10%,冲击波压力增加了8%。深冷激光冲击通过抑制动态回复从而诱导高密度位错,进而显著改善材料强度,为深冷激光冲击强化机理的研究提供了参考。
Molecular dynamics simulation was used to simulate the dislocation propagation induced in single-crystal titanium under cryogenic conditions (77K). The influence of temperature on the dislocation propagation was analyzed by the common neighbor analysis (CNA) method. The effects of laser shock wave Impact propagation characteristics in [0001] direction under cryogenic and ambient conditions. The results show that the laser shock wave of single crystal titanium in the direction of [0001] is an elastic-plastic double-wave structure. There are a lot of dislocations inside the material after laser shock wave in cryogenic environment, and the plastic deformation mainly shows the emission and propagation of incomplete dislocation. Impact stress and shear stress have a linear relationship with laser shock wave velocity. Laser shock wave velocity and shock wave pressure in cryogenic environment are higher than normal temperature, the shock wave velocity increased by 9% ~ 10%, shock wave pressure increased by 8%. The cryogenic laser shock can induce high density dislocation by restraining the dynamic recovery, and then improve the material strength remarkably, which provides a reference for the research of cryogenic laser shock enhancement mechanism.