The influence of kissing bond defect on the tensile properties, fracture toughness and fatigue crack growth rates were investigated on friction stir welded (FSW) AA5083-H112 alloy.

The tensile strength and elongation were significantly lower for welds having kissing bond as compared to sound FSW welds and parent material. The FSW weld joints with kissing bond failed in the face bend test configuration, while the same passed the root bend test.

The fractography analysis reveals that the face bend failure is occurring mainly through the kissing bond defect. Crack tip opening displacement value of kissing bonded FSW weld was found to be greater than parent material and lower than defect free friction stir welds.

Microstructural refinement was responsible for increase in fracture toughness as compared with parent material while secondary crack in the vicinity of kissing bond defect was responsible for lowering fracture toughness as compared with sound welds. A colour metallography method is proposed for the effective detection of kissing bond defects in FSW weld joint.

This article is shared by A.G. Rao, S. Gaidhani, A.P. Singh, V. Shrivastava, S. Pilli and V. P. Deshmukh