7A52铝合金等离子弧焊接头盐雾腐蚀行为研究

摘要

目的 研究7A52装甲铝合金等离子弧焊接接头耐海洋大气环境的腐蚀特征和规律.方法 通过盐雾加速腐蚀试验进行腐蚀评估,并在腐蚀后利用扫描电子显微镜(SEM)观察腐蚀产物微观形貌,并分析腐蚀时间对腐蚀性能的影响,通过能谱(EDS)分析腐蚀产物的元素组成.结果 7A52铝合金焊接接头盐雾腐蚀初期(8 h)热影响区首先出现点蚀,随着腐蚀时间延长(12 h),母材和焊缝发生点蚀,热影响区腐蚀产物层氧的含量最多.结论 7A52装甲铝合金等离子弧焊接接头处热影响区是腐蚀敏感区,热影响区比焊缝区和母材区耐蚀性稍差.%ABSTRACT: Objective To study corrosion behaviors and rules of 7A52 aluminum alloy plasma arc welding joint in simulation of marine atmosphere environment. Methods The corrosion tests were carried out with salt water spray test. And then the sur-face morphologies were observed by scanning electron microscopy (SEM), the effect of corrosion time on corrosion behavior was discussed. The distribution of element of corrosion products were analyzed by EDS. Results Pitting corrosion was main morphology in the heat affected zone in the initial stage (8 h), pitting corrosion occurred in matrix and weld joint with time (12 h). The content of oxygen in the corrosion products of the heat affected zone was the most. Conclusion The heat affected zone of the 7A52 aluminum alloy is a sensitive area of corrosion. The corrosion resistance of heat affected zone is slightly worse than that of the matrix and the welding seam.