Strength and ductility synergy in Mg-11Al alloys via Sc-microalloyed dual-wire arc additive manufacturing

A dual-wire arc additive manufacturing (WAAM) strategy via in-situ alloying of AZ71 and Al-2Sc wires was proposed to fabricate a Mg-10.6Al-0.4Zn-0.2Mn-0.05Sc alloy, overcoming the limitation of wire fabrication and achieving synergistic improvement in strength and ductility. After heat treatment, the alloy achieves a yield strength ≥200 MPa with elongation ≥5.2%. In-situ formed Al8Mn4Sc acted as heterogeneous nuclei, refining the β-Mg17Al12 and enhancing its dissolution kinetics, thereby improving the ductility. Meanwhile, high Al solubility promotes the precipitation of high-density non-basal β-Mg17Al12 and strengthens the alloy. This work offers a novel methodology for producing high-performance WAAM Mg alloys.