Abstract The stress corrosion cracking behaviour of laser MIG-hybrid welded 7B05-T5 aluminum alloy joint was studied by using pre-cracked wedge-open loading (WOL) specimens immersed in 3.5 %NaCl solution. The critical stress intensity factor for stress corrosion cracking (KISCC), and the cracks propagation rate (da/dt) were determined. The stress corrosion cracking propagation mechanism of welded joints was analyzed by fracture scanning and microstructure analysis. The results illustrated that both the base metal (BM) and the heat-affected zone (HAZ) were susceptible to stress corrosion cracking (SCC), but the weld zone (WZ) was not sensitive to SCC. The fracture mode of the aluminum alloy in SCC appeared the intergranular and transgranular mixed fracture. It was considered that the coaction of anodic dissolution and hydrogen embritt-lement contributed to SCC.

中文翻译：

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激光-MIG混合焊接7B05-T5铝合金的应力腐蚀开裂行为

摘要 采用浸渍在3.5%NaCl溶液中的预开裂楔形张开加载（WOL）试样，研究了激光MIG-混合焊接7B05-T5铝合金接头的应力腐蚀开裂行为。确定了应力腐蚀开裂的临界应力强度因子 (KISCC) 和裂纹扩展速率 (da/dt)。通过断口扫描和显微组织分析，分析了焊接接头应力腐蚀裂纹扩展机制。结果表明，母材 (BM) 和热影响区 (HAZ) 均易受应力腐蚀开裂 (SCC) 影响，但焊接区 (WZ) 对 SCC 不敏感。铝合金在 SCC 中的断裂方式出现沿晶和穿晶混合断裂。