Microstructure refinement and mechanical properties enhancement of wire-arc additive manufactured 2219 aluminum alloy assisted by interlayer friction stir processing

High strength and ductility wire-arc additive manufacturing (WAAM) 2219 aluminum alloy have been fabricated with the assist of interlayer friction stir processing (FSP). The FSP brings about a significant microstructure refinement where the average grain size reached to about 5.2 μm. As compared to the WAAM counterpart, the microhardness, yield strength, and ultimate tensile strength of the WAAM + interlayer FSP component are increased from 65.3 ± 2.8 HV, 96 ± 2 MPa and 249 ± 3 MPa to 70.6 ± 3.4 HV, 106 ± 3 MPa and 278 ± 4 MPa, respectively. Meanwhile, the elongations along the horizontal and vertical direction are increasing to 23.7 ± 2.5% and 15.6 ± 1.3%. The improvement in the mechanical properties of the WAAM + interlayer FSP components can be attributed to the remarkable grain refinement, broken-up of the second phase and elimination of pores induced by interlayer FSP deformation. •The 2219 aluminum alloy thin-wall structure was fabricated by the interlayer friction stir processing (FSP) assisted wire-arc additive manufacturing (WAAM).•The interlayer FSP deformation resulted in remarkable grain refinement, broken-up of the second phase and elimination of pores in the WAAM as-deposited material.•The strength and ductility of WAAM 2219 aluminum alloy was enhanced after the interlayer FSP deformation.