Post-weld formability of friction stir welded Al alloy 5052

Friction stir (FS) welds in Al alloys could be used as tailor welded blanks in automotive industry. Tailor welded blanks must exhibit adequate formability similar to that of the base material sheet. To evaluate the formability of FS welds in Al alloys for car body applications, a relationship between the fracture limit strain of plane strain deformation and the microstructure was examined in a FS welded thin Al alloy 5052 sheet. The fracture limit strain of plane strain deformation increased with increasing subgrain size in the stir zone. The present study suggests that the excellent fracture limit strain is attributed to the microstructure having both large grain size and a low density of dislocations and sub-boundaries in the stir zone of Al alloy 5052.