Shi Xuan, Zhang Sai, Li Tao, Meng Xianming, Cheng Congqian, Pei Jibin, Cao Tieshan, Zhao Jie
School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China.
China Automotive Technology and Research Center Co., Ltd., Tianjin 300300, China.
Materials (Basel). 2024 May 21;17(11):2472. doi: 10.3390/ma17112472.
Corrosion behavior is critical to the application of lightweight aluminum/steel joints using new resistance spot welding (RSW) technology. The study investigated the corrosion mechanism and the shear strength of RSW joints comprising 1.2 mm 5182 aluminum and 1.5 mm DP780 galvanized steel. Electrochemical corrosion tests were conducted on the base materials and various positions of the welds in a 3.5% NaCl solution. This result revealed that the corrosion susceptibility of the interfacial intermetallic compound (IMC) layer was not accelerated by the aluminum nugget because of the noble corrosion potential. Subsequently, the spray acceleration test was employed to investigate the corrosion mechanism. It is noteworthy that microcracks, as well as regions enriched with silicon and oxygen at the interface front, are preferential to corrosion during salt spray exposure, instead of the IMC layer. Moreover, the shear strength of the joints decreases with the reduction in the effective joint area after the salt spray exposure of the weld joints. This research systematically explored the corrosion behavior and its relationship with the mechanical properties of Al alloy/steel RSW joints.
腐蚀行为对于采用新型电阻点焊（RSW）技术的轻质铝/钢接头的应用至关重要。该研究调查了由1.2毫米5182铝合金和1.5毫米DP780镀锌钢组成的电阻点焊接头的腐蚀机制和抗剪强度。在3.5%的NaCl溶液中对母材和焊缝的不同位置进行了电化学腐蚀试验。结果表明，由于腐蚀电位较高，铝熔核并未加速界面金属间化合物（IMC）层的腐蚀敏感性。随后，采用喷雾加速试验来研究腐蚀机制。值得注意的是，在盐雾暴露期间，微裂纹以及界面前沿富含硅和氧的区域比IMC层更易发生腐蚀。此外，焊缝经盐雾暴露后，接头的抗剪强度随着有效接头面积的减小而降低。本研究系统地探讨了铝合金/钢电阻点焊接头的腐蚀行为及其与力学性能的关系。
