Synergic enhancement of strength and ductility in wire arc additively manufactured Ti-Cu alloys

The insignificant heterogeneous deformation behavior between eutectoid structure (ES, lamellar Ti2Cu + alpha') and oversaturated alpha' in additively manufactured Ti-Cu alloys leads to severe strength-ductility trade-off. In the current work, the Cu-solute diffusion in oversaturated alpha' was cleverly promoted by employing the large-heat-input gas metal arc-based wire arc additive manufacturing (GMA-WAAM). A balanced phase ratio of 1:1 and a prominent hardness difference of 3.4 GPa between ES and alpha' was achieved. Therefore, a significant heterogeneous deformation behavior was triggered, as indicated by the generated geometrically necessary dislocations (GNDs) of 3.45 x 10(15) m(-2) during the tensile process. The component exhibited a yield strength of 971 MPa and an elongation to fracture of 11.6 %, demonstrating a synergic enhancement of strength and ductility.