铜箔激光冲击微成形微观组织与残余应力研究

为了研究激光成形方式对成形轮廓和微观组织的影响，采用厚度为40μm和80μm的T2铜箔进行激光冲击微胀形和微拉深实验。同时使用ABAQUS有限元仿真对实验进行模拟，研究不同变形方式下箔材位移和残余应力场。结果表明，激光冲击微胀形后铜箔变形区域出现颈缩，激光作用区域内变形机制主要为位错滑移、变形扭曲晶粒和机械孪晶；箔材上表面（激光冲击表面）为残余拉应力，最大值约为372.3MPa，箔材下表面（背向激光冲击面）为残余压应力，最大值约为-218.7MPa；而对于微拉深，箔材成形轮廓过渡圆滑，厚度分布均匀，光斑作用区域内出现大量位错露头和一些机械孪晶，箔材上表面为残余压应力，最大值约为-365.6MPa，箔材下表面为残余拉应力，最大值约为203MPa。这一结果对激光冲击箔材成形控制是有帮助的。

Research of microstructure and residual stress of copper foils processed by laser shock forming

In order to study influence of laser forming methods on forming profile and microstructure, T2 copper foils with thickness of 40μm and 80μm were used to do experiments of laser shock micro bulging and micro deep drawing. At the same time, ABAQUS finite element simulation was used to simulate the experiment, and the displacement and residual stress field of the foil under different deformation modes were studied. The results show that, after bulging, necking occurs in the deformed region of copper foils. The deformation mechanism mainly includes dislocation sliding, deformation distortion grain and mechanical twinning in the laser processed region. The upper surface of the foil (laser shock surface) is residual tensile stress and the maximum value is about 372.3MPa. The lower surface of the foil (the opposite of laser shock surface) is residual compressive stress and the maximum value is about -218.7MPa. For drawing, foil forming profile is smooth and has uniform thickness distribution. A large number of dislocations and mechanical twinning appear in laser processed region. The upper surface of the foil is residual compressive stress and the maximum value is about -365.6MPa. The lower surface of the foil is residual tensile stress and the maximum value is about 203MPa. This result is helpful for the control of laser shock forming of foil.