Influence of travel speed on microstructure and mechanical properties of wire + arc additively manufactured 2219 aluminum alloy

Wire + arc additive manufacturing (WAAM) was preliminarily employed to fabricate the 2219 aluminum alloy. The influence of the electric arc travel speed (TS) on the macro-morphology, microstructure, and mechanical properties were investigated. The results indicated that as the electric arc TS increased, the size and the volume fraction of equiaxed grain decreased. The high arc TS during WAAM also promoted the precipitation of the θ (Al₂Cu) phase. The volume fractions of θ″ and θ′ phases reached maximum values when TS is 350 and 250 mm/min, respectively. The thermal cycle facilitated the precipitation of the θ′ phase. In addition, the micro-hardness and tensile strength of the alloy were analyzed, and the results indicated that samples fabricated at TS of 350 mm/min possessed finer equiaxed grain and exhibited higher ultimate tensile strength (273.5 MPa) and yield strength (182.9 MPa) compared to those fabricated at 250 mm/min.