Spherical MoSiBTiC alloy powder with little internal gas pores and cracks was successfully fabricated using plasma-spheroidization method. This powder fabrication process significantly decreased the oxygen content of the raw crushed powder. Then, MoSiBTiC alloy samples were fabricated via selective laser melting (SLM) with the plasma-spheroidized powder, and the microstructural characteristics and mechanical property were investigated. The as-built MoSiBTiC alloy exhibited a bimodal microstructure; the microstructure inside the melt pool (MP) was different from that at a melt pool boundary (MPB). The microstructure inside the MP consisted of primary Mo solid solution (Mo_ss) dendrites, and other constituent phases, such as Mo₅SiB₂ (T₂) phase, were formed at the inter-dendritic regions. On the other hand, (Ti,Mo)C precipitates around the Mo_ss dendrites were preferentially coarsened at the MPB, forming a heat affected zone (HAZ) at the underside within the MPB. At the upside within the MPB, the microstructure of the previous layer was partially remelted, and ternary eutectic lamellar structure (Mo_ss/T₂/(Mo,Ti)₂C) was newly formed. The as-built samples were subsequently subjected to heat treatment at different temperatures of 1600, 1700, and 1800 °C for 4 h. With increasing in the heat-treatment temperature, the Mo_ss dendritic microstructure decomposed, and other constituent phases were coarsened at the inter-dendritic regions. Through a detail microstructural characterization of both the as-built and heat-treated samples, it was confirmed that any large oxide was not formed in this study. Rapid solidification via SLM resulted in the refinement of microstructure and the formation of a supersaturated Mo_ss phase, which hardened the as-built sample but simultaneously decreased the crack resistance of the Mo_ss phase.

采用等离子球化法成功地制备了内部气孔和裂纹少的球形MoSiBTiC合金粉末。该粉末制造过程显着降低了原始压碎粉末的氧含量。然后，通过等离子球化粉末通过选择性激光熔化（SLM）制备了MoSiBTiC合金样品，并研究了其显微组织特性和力学性能。制成的MoSiBTiC合金表现出双峰显微组织。熔池（MP）内部的微观结构不同于熔池边界（MPB）的微观结构。MP内部的微观结构由主要的Mo固溶体（Mo _ss）树枝状晶体和其他组成相组成，例如Mo ₅ SiB ₂（T ₂相）形成在树突间区域。另一方面，Mo _ss树枝晶周围的（Ti，Mo）C析出物在MPB处优先变粗，在MPB的下侧形成热影响区（HAZ）。在MPB的上部，前一层的微观结构被部分重熔，并且新形成了三元共晶层状结构（Mo _ss / T ₂ /（Mo，Ti）₂ C）。随后将制成的样品在1600、1700和1800°C的不同温度下热处理4小时。随着热处理温度的升高，Mo _ss树枝状组织分解，其他组成相在树枝状间区域粗化。通过对竣工和热处理样品的详细微观结构表征，可以确定在该研究中没有形成任何大的氧化物。通过SLM的快速凝固导致了微结构的细化和过饱和Mo _ss相的形成，这使刚制成的样品硬化，但同时降低了Mo _ss相的抗裂性。