AZ31镁合金搅拌摩擦焊焊缝电化学性能的分析

试验的样品为3 mm厚挤压态AZ31镁合金,采用搅拌摩擦焊接工艺对焊而成.通过静态失重法、动电位极化曲线以及交流阻抗谱(electrochemical impedance spectroscopy,EIS)测试,研究了室温下浓度5%(质量分数)NaCl溶液中AZ31镁合金搅拌摩擦焊焊缝和母材的电化学行为.结果表明,在室温腐蚀介质中通过静态失重法测得AZ31镁合金母材和焊缝在168 h后的平均腐蚀速率分别为0.154和0.135 g/(m2·h),通过动电位极化曲线及交流阻抗谱(EIS)测得AZ31镁合金母材和焊缝的腐蚀电流分别为0.001 63和0.000 45 A/cm2,极化电阻分别为9.553和12.61Ω/cm2.AZ31镁合金搅拌摩擦焊焊缝的抗腐蚀性能优于其母材的表现.

Analysis of electrochemical property of AZ31 magnesium alloy friction stir weld

Friction stir butt welding of 3 mm thick AZ31 extruded magnesium alloy sheet was conducted. The electrochemical behaviors of AZ31 magnesium alloy friction stir weld and the parent metal were studied with static weight loss method, potentiodynamic polarization curve and electrochemical impedance spectroscopy(EIS) test in 5% NaCl aqueous solution at room temperature. The results indicate the average corrosion rates of AZ31 parent metal and weld after 168 hours' immersion were 0.154 and 0.135 g/(m2·h), respectively; the corrosion current densities of AZ31 parent metal and weld were 0.001 63 and 0.000 45 A/cm2, respectively; the polarization resistance were 9.553 and 12.61 Ω/cm2, respectively. The results show that the anti-corrosion property of AZ31 friction stir weld was better than that of the parent metal.