In-Situ Reduction of Mo-Based Composite Particles during Laser Powder Bed Fusion
Suxia Guo,
Weiwei Zhou,
Zhenxing Zhou,
Yuchi Fan,
Wei Luo,
Naoyuki Nomura
Affiliations
Suxia Guo
Department of Materials Processing, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan
Weiwei Zhou
Department of Materials Processing, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan
Zhenxing Zhou
Department of Materials Processing, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan
Yuchi Fan
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Institute of Functional Materials, Donghua University, Shanghai 201620, China
Wei Luo
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Institute of Functional Materials, Donghua University, Shanghai 201620, China
Naoyuki Nomura
Department of Materials Processing, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan
Raw powders are processed in water during the freeze-dry pulsated orifice ejection method (FD-POEM), leading to the inclusion of oxygen impurities. This study proposes a strategy for removing the oxygen content and enhancing the mechanical performance of laser powder bed fusion (L-PBF) builds from powders using carbon nanotubes (CNTs) and H2 reduction. Spherical 1.5 wt.% CNT/Mo composite powders with uniform dispersion were fabricated via FD-POEM. The quantity of MoO2 decreased significantly, and a hexagonally structured Mo2C phase was simultaneously formed in the L-PBF build. The Mo2C with network structure was distributed along the boundaries of equiaxed Mo grains, leading to an increased Vickers hardness of the matrix. This study demonstrates the feasibility of fabricating oxygen-free and high-strength refractory parts during L-PBF for ultrahigh-temperature applications.
