Abstract:Refractory metals, including tungsten (W), tantalum (Ta), molybdenum (Mo), and niobium (Nb), play a vital role in industries, such as nuclear energy and aerospace, owing to their exceptional melting temperatures, thermal durability, and corrosion resistance. These metals have body-centered cubic crystal structure, characterized by limited slip systems and impeded dislocation motion, resulting in significant low-temperature brittleness, which poses challenges for the conventional processing. Additive manufacturing technique provides an innovative approach, enabling the production of intricate parts without molds, which significantly improves the efficiency of material usage. This review provides a comprehensive overview of the advancements in additive manufacturing techniques for the production of refractory metals, such as W, Ta, Mo, and Nb, particularly the laser powder bed fusion. In this review, the influence mechanisms of key process parameters (laser power, scan strategy, and powder characteristics) on the evolution of material microstructure, the formation of metallurgical defects, and mechanical properties were discussed. Generally, optimizing powder characteristics, such as sphericity, implementing substrate preheating, and formulating alloying strategies can significantly improve the densification and crack resistance of manufactured parts. Meanwhile, strictly controlling the oxygen impurity content and optimizing the energy density input are also the key factors to achieve the simultaneous improvement in strength and ductility of refractory metals. Although additive manufacturing technique provides an innovative solution for processing refractory metals, critical issues, such as residual stress control, microstructure and performance anisotropy, and process stability, still need to be addressed. This review not only provides a theoretical basis for the additive manufacturing of high-performance refractory metals, but also proposes forward-looking directions for their industrial application.