Microstructure and mechanical properties of 2219 aluminum alloy intersection weld by FSW and VPPA

FSW-VPPA intersection weld on 2219 aluminum of 6 mm thickness was perpendicularly conducted by friction stir welding(FSW) and variable polarity plasma arc(VPPA).Microstructure characteristics of intersection weld were studied, and the main cause of porosity of intersection weld was preliminarily analyzed.Finally a comparative study of tensile property and fracture morphology of intersection weld and VPPA weld were discussed.It showed that the microstructure of intersection weld was asymmetrical and inhomogeneous, and the microstructure of fusion zone(FZ) was mainly composed of α-Al matrix and(α-Al+CuAl₂) eutectics.Aggregation porosities were easily found at bond area(BA) and heat-affected zone(HAZ) nearby BA.The increasing of porosity which located at BA vicinity resulted in the decreasing of tensile strength and elongation after fracture of intersection weld.