Enhancing the Age‐Hardening Response of Laser Powder‐Bed Fusion WE43 Alloy through Microstructural Control

Age-hardening is the main strengthening mechanism for obtaining high-strength WE43 alloy components traditionally produced via casting. Laser powder-bed fusion (L-PBF) can produce high-density WE43 parts. However, standard postprocessing heat treatment parameters (T6) used for conventional WE43 lead to inferior mechanical performance in L-PBF WE43. Herein, the effect of direct aging (T5) and artificial age-hardening treatment (T6) under varying temperature and duration on the resulting microstructure and mechanical properties of L-PBF WE43 is investigated via in-depth microstructural and mechanical characterization. The grain structure, orientation, texture as well as the size and morphology of β ₁-Mg ₃Nd precipitates are analyzed via electron backscatter diffraction and transmission electron microscopy. Superior ductility is determined upon optimized T6 treatment (550 °C, 4 h/200 °C, 8 h) in comparison to the direct aging (200 °C, 8 h) of L-PBF WE43 due to the dissolution of neodymium-rich particles during solutionizing potentially allowing finer and more homogeneous particle distribution. The direct aging of L-PBF WE43 shows an improvement in microhardness (93.5 Hv0.2) and tensile strength (260.1 MPa) with reduced ductility compared to as-built L-PBF WE43. A combination of high strength (UTS: 263.1 MPa)/hardness (85.2 Hv0.2) along with good ductility (6.1%) is achieved by optimizing T6 treatment for L-PBF WE43.