Processability of thin-powdered Inconel X750 and TiC metal matrix composite by laser-directed energy deposition

The processability of pure Inconel X750 and Inconel X750 mixed with 15 vol. % of titanium carbide particulate through laser-directed energy deposition (l-DED) was evaluated. The powders used had a particle size in a range unusual to l-DED processing (0.18–24.05 μm); this case study presents difficulties in processing thin quadri-modal powder and describes possible measures to mitigate them, while also reporting, likely for the first time, on the l-DED processing of Inconel X750 and such related metal matrix composite (MMC). The choice in reinforcement particle size and composition aimed for a reduction in material density and insertion of additional reinforcement mechanisms. Both powders used were analyzed in an FT4 rheometer and compared to reference Inconel 625 powder. l-DED was made viable, but results show that the powders tested here represent a lower limit for the rheological properties accepted by usual l-DED systems. A methodology to quantify the stability of a given processing condition is presented and validated, also indicating that low powder flows are recommended when processing powders of this sort. Inconel X750 demonstrated sensibility to oxidation during processing as depletion of Al and Ti was detected in the deposits. Neither the MMC nor the pure material cracked or showed excessive porosity.