Investigations on the effects of friction stir welding parameters on intermetallic and defect formation in joining aluminum alloy to mild steel

► A welding window for FSW of Al 5186 to mild steel was determined. ► Range of heat input factor (HIF) was determined to produce IMCs and defect free joints. ► IMCs as Al5Fe2 and Al6Fe were indentified in weld nugget and at Al/Fe interface. ► The dissimilar FSW of Al 5186 to steel was very sensitive to the plunge depth.