PSI - Issue 60

Rohan Nair et al. / Procedia Structural Integrity 60 (2024) 93–114 Rohan Nair / StructuralIntegrity Procedia 00 (2023) 000–000

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Fig. 15: Stereo microscopic images of the cir-seam weld specimen showing different regions of the weld cross section along with the microhardness values (VHN, load: 50gf) at weld, interface, HAZ and parent material regions.

Fig. 16 shows the microstructures of the sheet to forging indicating weld zone, weld/parent metal interfaces on both sheet and ring sides and parent materials of sheet and forgings. Microstructural examination of the weld zone revealed typical dendritic structure across the weld specimen with isolated porosities in the range of 35-85 microns with no sign of weld cracks or lack of fusion or penetration. In Fig. 15, left side of weld corresponds to forging and right side of weld corresponds to shell. The microstructure of AA6061 sheet revealed slightly elongated grains with uniform distribution of second phase particles throughout the matrix.

Fig. 16: Optical photo micrographs of a) sheet-weld interface at 50X, b) weld at 50X. c) sheet-/weld interface eat 50X, d) sheet microstructure at 100X, e) weld at 200X.andf) forging microstructure at 100X.

Fig. 17 shows SEM fractographic image of tensile tested specimen in as welded condition showing dimple features, confirming ductile mode of failure.