Processing, Defect Formation, Microstructure, and Mechanical Properties of Additively Manufactured Refractory Metals: A Review

Refractory metals are critical materials for aerospace applications including engines and gas turbines that operate under extreme temperatures, owing to their high melting point and excellent properties at elevated temperatures. However, the primary challenge in processing and fabricating refractory metals arises from their distinctive melting points and thermal conductivity. Currently, additive manufacturing technology is regarded as one of the promising approaches for fabricating refractory metals. This paper provides a comprehensive overview of the ‘composition–process–defect–microstructure–performance’ relationship in refractory metals produced through laser powder bed fusion, laser-directed energy deposition, and electron beam selective melting, following an introduction to the principles and characteristics of additive manufacturing technology. Furthermore, this paper anticipates future development trends within this field.