工业大气环境对Al-Mg-Si合金腐蚀疲劳特性的影响  

Effect of Industrial Atmospheric Environment on Corrosion Fatigue Behavior of Al-Mg-Si Alloy

作　　者：孙晓光 王子晗 徐学旭 韩晓辉 李刚卿 刘智勇[2] SUN Xiaoguang;WANG Zihan;XU Xuexu;HAN Xiaohui;LI Gangqing;LIU Zhiyong(Technical Engineering Department,CRRC Qingdao Sifang Co.LTD.,Qingdao 266111,China;Corrosion and Protection Center,University of Science and.Technology Beijing,Beijing 100083,China)

机构地区：[1]中车青岛四方机车车辆股份有限公司技术工程部,青岛266111 [2]北京科技大学腐蚀与防护中心,北京100083

出　　处：《中国腐蚀与防护学报》2021年第4期501-507,共7页Journal of Chinese Society For Corrosion and Protection

基　　金：国家自然科学基金(52071017);国家重点研发计划(2017YFB0702300)。

摘　　要：使用力学性能测试、轴向力加载疲劳测试、扫描电子显微镜、电化学测试等手段,研究了模拟工业大气环境中Al-Mg-Si合金母材及其焊接接头的腐蚀疲劳特征。结果表明:Al-Mg-Si合金对接焊接接头的力学性能低于母材,而且在模拟工业大气环境中更易腐蚀。焊接接头的腐蚀疲劳敏感性更高,原因是其焊接缺陷处容易成为腐蚀疲劳裂纹优先萌生的区域,最终导致试样在焊缝区域发生疲劳断裂。The corrosion fatigue characteristics of the Al-Mg-Si alloy and its butt welded joints in a simulated industrial atmosphere are studied by means of mechanical performance test, axial force loading fatigue test, scanning electron microscope, electrochemical test and other methods. The results show that the mechanical properties of butt-welded joints of Al-Mg-Si alloy are lower than that of the base metal, and the welded joints are more prone to corrosion in the simulated industrial atmosphere. The corrosion fatigue sensitivity of welded joints is higher, the corrosion fatigue cracks of the base metal initiate from corrosion pits at grain boundaries, while the fatigue cracks of the welded joints initiate easily at the locations rich in welding defects and inclusions of the weld seam. The existence of large number of welding defects and Al2 O3 inclusions introduced during the welding process may be responsible to why the corrosion fatigue performance of the welded joints of Al-Mg-Si alloy is lower than that of the base metal. Besides, the presence of inclusions will induce stress concentration, and around which high-density lattice distortion areas will also emerge. These areas will act as anodes to be preferentially dissolved and thereby, where to become the priority area of corrosion fatigue crack initiation, eventually lead to fatigue fracture of the test piece. Therefore, for the actual production, the forming process and welding process should be optimized, and the number of welding defects and inclusions should be controlled, so as to improve the corrosion fatigue performance of the alloy.

关 键 词：AL-MG-SI合金 焊接接头 腐蚀疲劳特征 模拟工业大气 

分 类 号：TG174[金属学及工艺—金属表面处理]