TC4钛合金激光冲击强化塑性变形流动规律研究  

Flow Law of Plastic Deformation of TC4 Titanium Alloy by Laser Shock Peening

作　　者：廖新隆 苏波泳 徐硕 花国然[1] 王恒[1] 曹宇鹏[1] Liao Xinlong;Su Boyong;Xu Shuo;Hua Guoran;Wang Heng;Cao Yupeng(School of Mechanical Engineering,Nantong University,Nantong 226019,Jiangsu,China)

机构地区：[1]南通大学机械工程学院,江苏南通226019

出　　处：《中国激光》2023年第16期143-154,共12页Chinese Journal of Lasers

基　　金：国家重点研发计划(2019YFB2005305);江苏省教育厅面上项目(20KJB460010);江苏省研究生科研创新计划(KY⁃CX21_3081)。

摘　　要：以TC4钛合金为研究对象,采用数值模拟与试验相结合的方式,研究了激光冲击TC4钛合金表面金属塑性变形和体积流动规律,分析了塑性变形驱动金属表层体积流动、应力重构、晶粒细化的机制。研究结果表明:激光冲击塑性变形使得光斑中心区域材料向着边缘及材料内部流动。整体塑性变形体积数值计算结果显示:当功率密度为1.58、2.25、3.02 GW/cm^(2)时,表面凹坑体积大致等于内部正向变形体积与表面环状凸起体积之和,在无相变体积改变的情况下,试件整体塑性变形符合体积不变定律;不同激光功率密度作用下的表面残余应力分布与表面塑性变形分布规律大致相同,存在对应关系;表面凹坑变形、环状凸起变形、内部凸起变形各区域粒径尺寸分别为99、108、136 nm,晶粒细化程度在表面凹坑区、环状凸起变形区域、内部正向变形区域依次递减。此外,光斑边缘出现的微凸起变形在受到搭接激光冲击作用后,再次发生塑性变形,微凸起变形在冲击载荷方向被压回,向着材料内部流动;凹坑表面各光斑边缘处依旧存在较小的微凸起变形。Objective Laser shock peening(LSP)is an advanced surface modification technology that uses laser-induced shock waves as a direct source of force for the production of plastic deformations on the surface of metals.It can be used to regulate the surface quality of the material and improve its properties.Laser shock peening has several advantages over other surface modification techniques,such as high loading pressure,large influence range,and controllable impact area and loading pressure parameters,and can be easily automated.It has a wide range of applications in aerospace,automotive manufacturing,and marine engineering industries.The plastic deformation is the fundamental process for laser shock peening in the reconstruction of surface stress,improvement of surface morphology,and hardening of surface materials.This deformation is influenced by a complex nonlinear dynamic process that is dependent on various factors such as laser shock wave pressure decay,the dynamic yield strength of materials,plastic strain rate,internal dislocations,and microcracking of materials.In this study,the flow law of plastic deformation of the TC4 titanium alloy under the action of shock waves is analyzed by combining numerical simulations and experimental studies.The reliability of the numerical model is verified through experimental studies,and the volume changes of internal plastic deformations under different laser shock parameters are calculated based on the numerical model.Additionally,the influence of plastic flows on volume distribution,stress reconstruction,and internal grain distribution of the material is analyzed.Methods A TC4 titanium alloy is used in this study.A combination of numerical simulations and experiments is used to study the flow law of plastic deformation of the TC4 titanium alloy by laser shock peening.First,a numerical simulation model of the laser shock peening of a TC4 titanium alloy is established.The surface deformation and residual stress distributions in the numerical simulation are extracted and compa

关 键 词：激光技术 TC4钛合金 激光冲击波 塑性流动 残余应力 晶粒细化 

分 类 号：TN249[电子电信—物理电子学]