Through-thickness friction stir processing; a low-cost technique for fusion welds repair and modification in AA6061 alloy

In the present study, gasmetal arc welded (GMAW) joints of AA6061 alloy were subjected to the friction stir processing technique in the through-thickness direction (henceforth named trough-thickness FSP) to modify the surface and the bulk of the welds. Additionally, the effect of GMAW heat input on the microstructural and mechanical properties of the welds was investigated after processing. The results indicate that the majority of the welding defects would be eliminated. In addition, the mechanical properties including hardness, tensile strength were recovered. The processed welds showed tensile elongation up to 12% and tensile fracture occurred in base metal. the microstructure of the weld was modified as well in whole thickness of the welds.