Laser Powder-Bed Fusion of a Refractory High-Entropy Alloy for Extreme Environments

Additive manufacturing (AM) of refractory high-entropy alloys (RHEAs) offers a promising solution for extreme environments in space exploration due to their exceptional thermal stability, strength, and resistance to oxidation, erosion, radiation, and so on. Here, we report the laser powder-bed fusion (LPBF) processing of MoNbTaW RHEA with a highest melting point possible that can withstand the extreme temperatures and radiation. LPBF enables the direct fabrication of complex, near-net-shape components while reducing material waste and manufacturing time. This research shows that LPBF can be employed to fabricate RHEAs with tailored microstructures for superior performance in space applications. Several key processing challenges include mitigating lack of fusion and hot cracking, controlling microstructural heterogeneity, managing residual stresses, and reducing ductile-to-brittle transition temperature. The preliminary results will be discussed in terms of the technical challenges mentioned-above.