Microstructure and mechanical properties of Mg-Gd-Y-Al-Mn alloys fabricated by wire arc additive manufacturing

• The WAAM Mg-Gd-Y-Al alloy exhibits a fine equiaxed grain structure . • The thermally stable Al-Mn-RE phase is capable of pinning the grain boundary to improve the thermal stability of the grains. • Acquires better combined mechanical properties of YS (211 MPa), UTS (290 MPa), and EL (4.8 %). Wire arc additive manufacturing (WAAM) is an effective fabrication technology for preparing high-performance magnesium alloy components. In this paper, a heat-treatable Mg-10Gd-3Y-1Al-1Mn (GWAM10311) alloy for WAAM was designed. The results show that the as-deposited alloy exhibits a uniform equiaxed grain structure with an average grain size of 15.9 μm. After solution treatment at 520 °C for 12 h, the grain size remained stable (16.9 μm), demonstrating excellent thermal stability. Aging treatment induces the formation of a high-density nano-sized β' phase within the matrix, significantly enhancing the mechanical properties of the alloy. The yield strength (YS), ultimate tensile strength (UTS), and elongation (EL) reach 211 MPa, 290 MPa, and 4.8 %, respectively. This study provides a theoretical proof for developing high-performance magnesium alloys for WAAM.