Material Flow Behavior in Dissimilar Friction Stir Welds of AA2024 and AA5086 Aluminum alloys

Abstract

This research aims to investigate the material flow behaviour and microstructure evolution in friction stir welded joints of dissimilar aluminium alloys AA2024/AA5086. AA2024 plate was placed on re- treating side; welded using threaded conical flat shoulder tool rotating at 635 rpm and moving along the joint line with a speed of 75mm/min. Mixing of both the material was clearly visible in stir zone and resulted in features typical to dissimilar friction stir welding and solid state flow patterns beside different zones. Onion rings, laminar flow, vertex flow was main flow features observed in the stir zone. Non- uniform mixing of different chemical composition base material is behind the formation of these flow features and inclusive chemical mixing may abolish solid state flow features.