Microstructure and strain hardening behaviour at the inter-mixing zone of water-cooled friction stir welded dissimilar aluminum alloys

Abstract

• The strain hardening behaviour at the inter-mixing zone of FSW was investigated. • Strain hardening behaviour was correlated with grain size, grain boundary wetting and texture. • The WCFSW joint resulted in higher tensile strength and strain hardening rate. The present study investigated the effect of water-cooling friction stir welding (WCFSW) on microstructure characteristics and strain hardening behaviour along the intermixing zone or stir zone of dissimilar 5083-6061 aluminum alloys. Results indicated that WCFSW had refined grain structure, high dislocation density and finer intermetallic compound formation due to intense plastic deformation at the stir zone. Textures components such as Brass [{1 1 0} 〈1 1 2〉] and Goss [{1 1 0} 〈0 0 1〉] were predominantly evolved in FSW samples. The tensile strength and strain hardening rate were maximum in the WCFSW joint attributed to finer grains, higher dislocation density and texture evolved.