Microstructure and Properties of FSW Butt Joints Made of Differently Combined 6082T6 and 1565chM Aluminum Alloys

The results of experimental studies of one-sided friction stir welding of 10-mm-thick plates made of aluminum alloys 6082T6 (pressed profile) and 1565chM (the sheet positioned upstream of the working tool) are presented. Welded butt joints without internal defects are obtained. The tensile strength of the joints averages 210.9 MPa, which is 0.69 of the strength obtained for alloy 6082T6. The fracture of welds during the tensile test develops in the heat-affected zone on the side of alloy 6082T6. The tensile strength of the metal of the mixing zone is higher than that of alloy 6082T6. It is almost the same as for alloy 1565chM. The microstructure of the mixing zone consists of areas featuring a chemical composition corresponding to the chemical composition of the alloys to be welded or to the areas having partial mixing of alloys to be joined. At the same time, the metal of the mixing zone is resistant to intercrystalline corrosion. The heat-affected zone on the side of the 6082T6 alloy is the most susceptible to intercrystalline corrosion.