An investigation into microstructures and properties of 7075-t6 during friction stir welding

Microstructural and mechanical properties of friction stir welded 4mm7075-T6 aluminum alloy were investigated in this paper. The microstructures in WAZ, TMAZ and HAZ were analyzed. The results show that with the rotating speed at 1500 rpm and welding speed at 60mm/min, a defect-free welding joint was obtained. The tensile strength was 362 MPa, which is 65% of base metals; Weld nugget is composed of equiaxed grains; The lowest hardness between the TMAZ and HAZ of advancing side. The fractography revealed that samples failed in ductile mode and the strain fracture appears in advancing side of weld zone. © (2013) Trans Tech Publications, Switzerland.