Microstructure Evaluation of Friction Stir Welded AZ91 with CaO Mg Alloy

The present study was carried out to evaluate the microstructural properties of a friction stir welded AZ91 with CaO Mg alloy. For this work, friction stir welding (FSW) was performed at a tool rotation speed of 1250 rpm and a traveling speed of 32 mm·min−1. A network of intermetallic compounds (Al2Ca) was observed in the base metal (BM). In the stir zone (SZ), fine grains and intermetallic compound particles were formed due to dynamic recrystalization and mechanical stirring. The hardness profile showed that the hardness of the SZ was higher than that of the BM, probably due to the presence of fine grains and thermally stable intermetallic compounds.