深冷环境下激光冲击波在单晶钛中的传播及位错扩展特性  

Propagation and Dislocation Development Properties of Laser Shock Waves in Monocrystalline Titanium Under Cryogenic Environment

作　　者：徐高峰[1] 周建忠[1] 孟宪凯[1] 黄舒[1] 孙云辉[1] 徐洋洋[1] 

机构地区：[1]江苏大学机械工程学院,江苏镇江212013

出　　处：《中国激光》2017年第6期112-118,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(51575247;51405204);中国博士后科学基金(2014T70477;2013M540417);江苏大学高级人才启动基金(13JDG109);江苏省科技支撑项目(工业)(BE2013097);江苏省自然科学基金(BK20141166);江苏省研究生创新计划(KYLX15_1056)

摘　　要：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。The dislocation development induced in monocrystalline titanium under cryogenic environment （77 K） is simulated by using the molecular dynamics method. The effect of the temperature on the dislocation development is analyzed by using the common-neighbor analysis （CNA） method, and the propagation properties of laser shock waves along the [0001] direction under the cryogenic and room-temperature environments are investigated systematically. The results show that the laser shock waves along the [0001] direction exhibit an elastic-plastic two- wave structure. Under the cryogenic environment, a large number of dislocations occur within materials after the laser shock waves. The plastic deformation mainly manifests as the emission and the propagation of partial dislocations. The impact stress and the shear stress both have the linear relationship with the speed of shock waves. The speed and the pressure of laser shock waves under the cryogenic environment are both higher than those under the room-temperature environment. The speed increases by 9~//00-10% and the pressure increases by 8O//oo. By means of suppressing the dynamic recovery under the cryogenic environment, laser peening can induce high density dislocations and thus dramatically strengthen the material strength, which provides a reference for the investigation of laser shock peening mechanism under the cryogenic environment.

关 键 词：激光技术 深冷激光冲击 钛合金材料 位错 分子动力学 

分 类 号：TG17[金属学及工艺—金属表面处理]