A novel approach to develop aluminum matrix nano-composite employing friction stir welding technique: Fid-Bau Portal

A novel approach to develop aluminum matrix nano-composite employing friction stir welding technique

Bahrami, Mohsen / Dehghani, Kamran / Besharati Givi, Mohammad Kazem

Highlights • AA7075/SiC nano-composite developed employing friction stir welding technique. • 1250rpm and 40mm/min were the optimum welding speeds. • Increasing rotational speed resulted in improved powders dispersion. • An excellent bonding between reinforcement and the matrix was observed. • UTS and ductility improved by up to 31% and 76.1% due to grain size refinement associated with SiC nano-particles.

Abstract The main object of the present study is to investigate the effect of nano-sized SiC particle on the mechanical properties of the friction stir welding (FSW) joints. Prior to FSW, nano-sized SiC particles were incorporated into the joint line. A combination of three rotational speeds and three traveling speeds were applied. Microstructural evaluation using optical microscopy (OM) and scanning electron microscopy (SEM) revealed a banded structure consisting of particle-rich and particle-free regions in stir zone (SZ). The joints fabricated with rotational speed of 1250rpm and traveling speeds of 40 and 50mm/min, exhibited the highest mechanical properties. Owing to the presence of SiC nano-particles, at 1250rpm and 40mm/min, ultimate tensile strength (UTS) and percentage of elongation were improved by 31% and 76.1%, respectively. Significant increase in UTS and percentage of elongation were attributed to the pinning effect and increased nucleation sites associated with SiC nano-particles. Moreover, reinforcement particles resulted in breaking of primary grains. On the other hand, at 1250rpm and 40mm/min, SiC-included specimen showed superior ductility to SiC-free specimen. The fracture morphologies were in good agreement with corresponding ductility results.