Powder Fabrication and Laser Powder Bed Fusion of a MoSiBTiC-La2O3 Alloy

Abstract

In the present work, an approach of freeze-dry pulsated orifice ejection method (FD-POEM) was utilized to fabricate monodispersed MoSiBTiC-La2O3 composite powders for laser powder bed fusion (L-PBF). The FD-POEM powders were spherically shaped, possessing a narrow size range and uniform element distribution. As revealed by the single-track and single-layer experiments, the porous FD-POEM particles were sufficiently fused under laser irradiation, leading to the generation of continuous laser tracks and low surface roughness layers, which proved a feasible L-PBF processability of MoSiBTiC-La2O3 powders. Careful microstructural observations confirmed that the microstructure of the molten pools was primarily composed of Mo solid solution dendrites reinforced with La2O3 nanoparticles. Consequently, the single MoSiBTiC-La2O3 track had a high Martens hardness of 3955 HM. The result of this work reveals that the combination of FD-POEM and L-PBF has a great potential of developing advanced heat-resistant Mo-based alloys with tailored structures for ultrahigh-temperature applications.