The microstructures and mechanical properties of friction stir welded AZ31 with CaO Mg alloys

The present study was carried out to evaluate the microstructural and mechanical properties of a friction stir welded AZ31 with CaO Mg alloys. Friction stir welding (FSW) was performed at a tool rotation speed of 1600 rpm and a traveling speed of 80 mm/min. An intermetallic compound, Al2Ca, was resulted in the base metal (BM). In the stir zone (SZ), fine grains and intermetallic compound particles formed due to dynamic recrystallization and mechanical stirring. Hardness profiling showed that the SZ was harder than the BM, likely due to the presence of fine grains and thermally stable intermetallic compounds.

► AZ31 Mg alloys were friction stir welded.
► Grains were finer with increasing of CaO contents after friction stir welding.
► Pinning effect was occurred in the SZ due to Al2Ca intermetallic compounds.
► AZ31 with CaO alloys show superior mechanical property after friction stir welding.
► Abnormal grain growth was not occurred in the AZ31 with CaO alloys after friction stir welding.