Wire-based friction stir additive manufacturing of AlCu alloy with forging mechanical properties

Abstract

Aluminum‑copper (AlCu) alloy load-bearing structures fabricated via fusion-based additive-manufacturing methods are highly sensitive to the occurrence of porosities during solidification and grain coarsening during high energy input, which is yet to be appropriately addressed in printing high-performance components. Here, a novel additive manufacturing technology named wire-based friction stir additive manufacturing (W-FSAM) was proposed to fabricate high-strength AlCu alloy load-bearing parts with ultrafine-grained structures and uniformly dispersed precipitates. Ultrafine equiaxed grains were obtained with the grain size of about 1.62 ± 0.26 μm. A large amount of θ' phases were uniformly precipitated after heat-treated process. The mechanical properties of W-FSAM AlCu alloy specimens reached 283.0 ± 2.7 MPa and 413.7 ± 6.7 MPa in terms of yield strength and ultimate tensile strength after heat-treated process, which mechanical properties have reached the forging parts. Precipitate strengthening accounted for 70.4 % of strengthening factors was considered as the main strengthening mechanism. These mechanical properties are expected to have options for fabricating high-performance bear-loading structures of AlCu alloys.