Effects of TiC on the microstructure refinement and mechanical property enhancement of additive manufactured Inconel 625/TiC metal matrix composites fabricated with novel core-shell composite powder

The flexible product shape of additive manufacturing (AM) is attractive, but the process suffers from a lack of material property diversity due to a limited number of printable alloys and post-processing options. To overcome this problem, the AM of metal matrix composites (MMCs) is a highly suitable solution because the properties of MMC can be tailored using various reinforcements. Therefore, extensive research has been conducted on the AM of MMCs; however, the major huddle for this process has been the difficulties in preparing feedstock powder and operating the AM process. This study introduces an easily synthesizable core-shell composite powder, which was fabricated by a recently developed process called the SMART process. The core-shell powder has a novel morphology, consisting of a metal core and composite shell, distinguishing it from the powders used in conventional AM approaches. Inconel 625/TiCp composites were fabricated using the core-shell composite powder, with various fractions of TiCp up to 10 vol.%. Compared to additive-manufactured Inconel 625, the additive-manufactured MMCs showed enhanced strength with significantly fewer defects. The results of this study may accelerate the application of MMC fabricated by AM, which offers superior properties and reliability compared to casting and powder metallurgy due to the higher degree of dislocation density and reinforcement dispersion.