Understanding Process and Property Relationships in Aluminum Alloy Friction Stir Welds

Friction stir welding (FSW) has been in use for nearly fifteen years and a significant body of published research regarding process/property/structure relationships is now available; particularly with respect to FSW of aluminum alloys. In this paper, some pertinent literature will be reviewed and an attempt made to tie the numerous experimental observations together through some unifying concepts. Examination of relationships among control and response FSW process variables (respectively e.g. tool rotation rate and torque) and weld microstructure and properties can provide important insight regarding how weld properties develop and how best to approach process development for different alloy classes.