Stationary Shoulder Friction Stir Assisted Scribe Technique for Dissimilar Joining

Abstract

We report on implementation of a stationary shoulder in dissimilar joints of Al-steel and Al-carbon fiber reinforced polymer (CFRP) using friction stir assisted scribe technology (FaST). Viable joint strength similar to the conventional FaST process was demonstrated in Al-Steel. A significant improvement in as-welded surface roughness for both Al-steel and Al-CFRP cases was also achieved. Interrupted lap shear tests performed on Al-steel joints and a corresponding computational model indicate the joint failure typically occurs in Al sheet via a crack that originates at the steel hook tip on the loading side. A similar fracture path was observed in an Al-CFRP joint.