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研究高速列车A7N01S-T5铝合金母材及焊接接头的晶间腐蚀行为,测定和观察腐蚀失重、硬度变化、断面和表面形貌。结果表明,在含氯的腐蚀介质中,焊接接头的腐蚀速率高于母材,热影响区是接头腐蚀最为严重的区域,腐蚀沿晶界扩展,形成网状裂纹。焊接热输入使热影响区的富锌强化相沿晶界连续析出,其电位最低因而成为腐蚀电池的阳极,不断发生电化学反应而溶解,导致晶界成为腐蚀的阳极活性通道,使腐蚀沿不断向金属内部发展。
Study on the intergranular corrosion behavior of A7N01S-T5 aluminum alloy high-speed train and welded joint of high-speed train and measure and observe corrosion weight loss, hardness change, section and surface topography. The results show that the corrosion rate of welded joint is higher than that of base metal in the corrosion medium containing chlorine, and the HAZ is the area where joint corrosion is the most serious. The corrosion expands along the grain boundary to form a net-shaped crack. Welding heat input makes the heat-affected zone of zinc-rich reinforcing phase continuous precipitation along the grain boundary, the lowest potential and thus become the corrosion of the battery anode, electrochemical reactions continue to dissolve, leading to corrosion of the grain boundary become active anode channel, so that corrosion along the constantly Metal interior development.