Microstructure and heat treatment investigation of Inconel 625/TiC composite produced by Laser Powder Bed Fusion

Inconel 625 (IN625) is a Ni-based superalloy characterized by good mechanical performance and excellent oxidation resistance up to 1000°C. In order to enhance the mechanical performances of the IN625, ceramic particles can be added to the alloy. In the current work, the IN625 powder was mixed with submicrometric TiC particles and then processed by the laser powder bed fusion (LPBF) process. The microstructure of the as-built and heat-treated composite was compared to the base alloy in order to investigate the variations in terms of microstructure. The as-built condition of the IN625 and composite exhibited columnar grains with very fine dendritic structure along the building direction. Differently, a high-temperature solution annealing involved recrystallization of the IN625 samples while the composite still presented columnar grains, thus showing higher microstructure stability at elevated temperatures.