Experimental investigation of material flow during friction stir spot welding

Material flow during friction stir spot welding is investigated by experimental approaches in this study. Different kinds of fine wires and WC powder are used as trace material and disposed in the interface between upper material and lower material. After spot welding, detailed microscopic observations are carried out in the various sections. Continuous distributions of tracer materials are investigated during friction stir spot welding. Three-dimensional material flow model is proposed by the combination of the results, which are obtained in the present study and previous studies.