Microstructure and mechanical properties of WE43 magnesium alloy fabricated by wire-arc additive manufacturing

Wire-arc additive manufacturing (WAAM) is emerging as a revolutionary method for fabricating heat-resistant WE43 magnesium alloy (WE43-Mg) components and multiple other Mg alloys. In this study, we successfully utilized cold metal transfer WAAM technology to fabricate high quality single-pass thin-walled WE43-Mg structures. The results show that the microstructure is mainly composed of equiaxed grains, and Mg14Nd2(Y, Gd) is the main second phase distributed along the grain boundaries. The relative density of the sample reaches 99.96 %, and the main defects are oxide inclusions. The room temperature yield strength, ultimate tensile strength and elongation are 147.0 MPa, 221.9 MPa and 7.2 %, respectively, with anisotropy rates of 1.9 %, 2.2 % and 3.7 %. High-temperature tensile tests conducted at 250 degrees C showed a slight increase in ultimate tensile strength and a significant increase in elongation from 7.2 % to 16.8 %, representing a 133 % increase. Under these conditions, the proportion of substructure increased significantly, and the proportion of low-angle grain boundaries rose from 3.2 % to 69 %. The stress-strain curves exhibited pronounced serrated flow behavior, which is attributed to the interaction between solute atoms and dislocations.