对20 mm厚7075铝合金搅拌摩擦焊(FSW)接头沿板厚方向进行分层晶间腐蚀行为研究。借助光学显微镜及扫描电子显微镜分析了接头组织、第二相成分及分布、腐蚀深度及接头各区腐蚀形貌。结果表明:焊缝中心区腐蚀程度最轻,热机影响区(TMAZ)次之,热影响区(HAZ)腐蚀程度最严重;沿板厚向下,焊核区(NZ)腐蚀程度逐渐变大,TMAZ腐蚀程度先变大后减小,HAZ腐蚀程度逐渐减小;接头沿板厚方向晶粒大小和第二相粒子尺寸及分布存在差异,是造成沿板厚方向各区不同晶间腐蚀程度的主要原因。 The interlamellar intergranular corrosion behavior along the thickness of 20 mm thick 7075 aluminum alloy friction stir welding (FSW) joint was studied. The microstructure of the joint, the composition and distribution of the second phase, the corrosion depth and the corrosion morphology of the joints were analyzed by optical microscopy and scanning electron microscopy. The results show that the corrosion zone in the weld zone is the least, the TMAZ zone is the second, and the HAZ zone is the most corrosive. Along the plate thickness, the corrosion zone in the weld zone (NZ) The corrosion degree of TMAZ first increases and then decreases, and the corrosion degree of HAZ decreases gradually. The difference of the grain size and the size and distribution of the second phase particles along the thickness direction of the joint is the main reason for the different intergranular corrosion along the thickness direction of the joint the reason.