采用极化曲线、电化学交流阻抗谱、X 射线衍射仪(XRD)测试残余应力、扫描电镜(SEM)测试腐蚀形貌从实验上研究了强激光冲击对7075 铝合金等离子弧焊接头电化学腐蚀行为的影响。研究结果表明，激光冲击后7075 铝合金焊接头表面残余应力由拉应力变成压应力，从而使得铝合金等离子弧焊接头的自腐蚀电位和点蚀电位提高，激光冲击4 次后自腐蚀电位正移700 mV，点蚀电位正移约为1000 mV，极化曲线上出现了电位范围至712.9 mV 的阳极钝化区间。经过激光冲击处理细化晶粒，7075 铝合金焊接头的显微孔洞数量和气穴的体积减少，组织致密性提高，溶液中Cl等原子的渗入被有效阻止，从而降低了腐蚀速率，使自腐蚀电流密度降低了1个数量级。激光冲击使焊接头处晶粒沿β相分布变得均匀，β相与α基相构成的微电偶的活性降低，钝化电阻比冲击前提高了近30 倍，浓差极化现象大为改善。

The effect of laser shock processing (LSP) on electrochemical corrosion behavior of 7075 aluminum alloy plasma arc weldments has been studied by using polarization curves, electrochemical impedance spectroscopy, residual stress tested by X- ray diffraction technique and scanning electron microscope (SEM) morphology of corrosion surface. The results show that the surface residual stress of weldments with LSP has been changed from tensile to compression, which leads to the improvement of the free-corrosion potential and pitting potential. The free-corrosion potential of weldments with 4 times LSP impacts is about 700 mV higher than that without LSP, and the pitting potential also occurs in about 1000 mV, besides the polarization curves exhibit an anode passivation zone in a wide range of potential with 712.9 mV. After grains being refined by LSP, the number of the microscopic holes and the volume of cavitation have been reduced, and the compactness of its surface microstructure has been improved. The infiltration of atoms such as Cl- in the NaCl solution has been effectively prevented, thereby the corrosion rate can be reduced, and the corrosion current density has been decreased by one orders of magnitude. The grains have been well-distributed along the β -phase in weldments with LSP. The activity of micro-galvanic made up of β phase and α base phase has been reduced, and the impact of passive resistance is nearly 30 times higher than that without LSP. Concentration polarization has been greatly improved.