Effect of Temperature on Tensile Properties of Laser Powder Bed Fusion Additively Manufactured Niobium Alloy C103

Niobium (Nb) alloy C103 is commonly used in high-temperature aerospace propulsion applications due to its strength at temperatures above 1200 degrees C and low ductile-to-brittle transition temperature. With the rise of interest in additive manufacturing (AM) for refractory material processing, it is crucial to ensure that the properties of AM-produced C103 match those of conventionally processed materials, particularly concerning ductility and high-temperature performance. This study evaluates C103 produced via laser powder bed fusion (L-PBF) by conducting uniaxial tensile tests from room temperature to 1400 degrees C in a high-vacuum environment and comparing the results to those of conventionally processed wrought C103 tested under identical conditions. Results from tensile testing indicated that as-built L-PBF C103 has comparable tensile properties to wrought (worked) C103, while hot isostatic pressing (HIP) post-processed L-PBF C103 exhibited similar properties to wrought (recrystallized) C103. In all conditions, whether L-PBF or wrought, C103 exhibited minima in tensile elongation in the 600-800 degrees C temperature range; however, this was not accompanied by a change in fracture mechanism. HIP post-processing marginally improved material density but significantly reduced low-to-intermediate temperature strength due to recovery of the microstructure and grain growth. These insights into the mechanical behavior of L-PBF C103 enhance confidence in its use for reliable high-temperature aerospace components.