(1. 江蘇大學(xué) 材料科學(xué)與工程學(xué)院，鎮(zhèn)江 212013；
2. 東南大學(xué) 機械工程學(xué)院，南京 210096)
摘 要: 為了研究激光沖擊強化對鎂合金表面形貌和電化學(xué)腐蝕性能的影響，采用電化學(xué)方法和釹玻璃脈沖激光(波長1064 nm，脈沖寬度20 ns)研究AZ31熱軋板和AZ91-T6鑄造鎂合金在3.5%NaCl(質(zhì)量分數(shù))溶液中的動態(tài)極化曲線和電化學(xué)阻抗譜特征，并對鎂合金三維表面形貌、腐蝕試樣宏觀形貌、自腐蝕電位和電化學(xué)阻抗譜進行測試與分析。結(jié)果表明：激光沖擊改善AZ31熱軋板和AZ91-T6鎂合金的耐蝕性。當(dāng)激光功率密度處于0.6~0.9 GW/cm2區(qū)間，鎂合金腐蝕電位和電流密度分別出現(xiàn)峰值和谷值；當(dāng)功率密度不小于1.0 GW/cm2時，鎂合金腐蝕電位和電流密度分別正負移動，與沖擊表面的形變、鈍化膜和形貌密切相關(guān)。
關(guān)鍵字: 鎂合金；激光沖擊強化；表面形貌；鈍化膜；電化學(xué)腐蝕性能
（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
