Development Of Nickel-based Superalloy 939 For LPBF Additive Manufacturing: Alloy Design, Microstructure, And Mechanical Properties

Nickel 939 alloy was originally developed as a cast superalloy for high-temperature applications, capable of withstanding temperatures up to 850°C in gas turbine components such as blades, vanes, and burner nozzles. However, the alloy exhibits poor weldability, with extensive microcracks commonly observed during laser powder bed fusion (LPBF) additive manufacturing. By employing alloy design approaches, we successfully modified the minor elemental composition of the 939 alloy, effectively eliminating microcracks in LPBF-fabricated parts. This paper discusses the alloy design approaches, optimisation of printing parameters, and the resulting mechanical properties, including both room-temperature and high-temperature performance. Additionally, the mechanical properties are analysed in relation to the microstructure and fractographic characteristics.