Improvements of strength and ductility in aluminum alloy joints via rapid cooling during friction stir welding

► Friction stir welding (FSW) significantly improves ductility of AA2219 Al alloy. ► UTS of the FSWed joints with water cooling reaches nearly that of the base metal. ► Air cooling results in a higher strain hardening capacity than water cooling. ► Top slice has a higher strength, lower ductility and strain hardening capacity.