(1. 江苏大学 材料科学与工程学院，镇江 212013；
2. 东南大学 机械工程学院，南京 210096)
摘 要: 为了研究激光冲击强化对镁合金表面形貌和电化学腐蚀性能的影响，采用电化学方法和钕玻璃脉冲激光(波长1064 nm，脉冲宽度20 ns)研究AZ31热轧板和AZ91-T6铸造镁合金在3.5%NaCl(质量分数)溶液中的动态极化曲线和电化学阻抗谱特征，并对镁合金三维表面形貌、腐蚀试样宏观形貌、自腐蚀电位和电化学阻抗谱进行测试与分析。结果表明：激光冲击改善AZ31热轧板和AZ91-T6镁合金的耐蚀性。当激光功率密度处于0.6~0.9 GW/cm2区间，镁合金腐蚀电位和电流密度分别出现峰值和谷值；当功率密度不小于1.0 GW/cm2时，镁合金腐蚀电位和电流密度分别正负移动，与冲击表面的形变、钝化膜和形貌密切相关。
关键字: 镁合金；激光冲击强化；表面形貌；钝化膜；电化学腐蚀性能
（1. School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China;
2. School of Mechanical Engineering, Southeast University, Nanjing 210096, China）
Abstract:In order to study the effect of laser shock processing (LSP) on the surface morphology and electrochemical corrosion resistance of magnesium alloys, the dynamic polarization curves and electrochemical impedance spectroscopy (EIS) of specimens of hot rolled sheet of AZ31 alloy and AZ91-T6 cast alloy in 3.5%NaCl (mass fraction) solution were investigated by electrochemical method and Nd:glass laser with the wavelength of 1064 nm and pulse width of 20 ns. The 3D surface morphology, macroscopic morphology of corrosion specimens, corrosion potential and electrochemical impedance spectroscopy (EIS) were also examined and analyzed. The results show that the corrosion resistance of hot rolled AZ31 alloy sheet and AZ91-T6 cast alloy are improved by LSP. When the laser power density is in the range from 0.6 GW/cm2 to 0.9GW/cm2, the peaks and valleys of the corrosion potential and the current density of magnesium alloy appear, respectively. When the power density is not less than 1.0 GW/cm2, the corrosion potential and current density of magnesium alloy begin to move towards positive and negative directions, respectively, which are closely related to the deformation, passivating film and morphology of the impact surface.
Key words: magnesium alloys; laser shock processing; surface morphology; passivating film; electrochemical corrosion resistance
