Effect of C-Mn-Cu on microstructure and properties of wire arc additive manufacturing of high-manganese steels.

This article focuses on the development and evaluation of metal powder-cored wires for wire arc additive manufacturing (WAAM) of high-manganese steels, emphasizing the effects of key alloying elements—carbon (C), manganese (Mn), and copper (Cu)—on microstructure, stacking fault energy (SFE), and mechanical properties. High-manganese steels with fully austenitic microstructures and SFE values above 20 mJ/m² were designed to promote twinning-induced plasticity (TWIP) and reduce martensitic transformation, enhancing strength, elongation, and toughness. Experimental results showed that increasing C content improved tensile strength and elongation up to an optimum (1.10% C), Mn content influenced strength and ductility inversely with an optimal range near 21%, and Cu content enhanced yield strength and elongation with peak impact toughness at about 0.98% Cu. The wire designated M3 (1.10%C, 21%Mn, 0.3%Cu) exhibited the best overall mechanical performance, combining high strength, good elongation, impact toughness, mechanical stability, and low susceptibility to solidification cracking.