Enhancing oxidation resistance of LPBF-fabricated NiCrAl alloys via TiC Particle Additions

This study systematically investigates the influence of TiC particles on the microstructure and high-temperature oxidation behavior of NiCrAl alloys fabricated by laser powder bed fusion (LPBF). Comparative analyses reveal that the incorporation of both 1 and 2 wt % TiC transforms the microstructure of LPBF NiCrAl alloys from a columnar subgrain structure to a refined cellular subgrain structure, accompanied by a crystallographic orientation shift from <111>/<101> to a dominant <001> texture. High-temperature oxidation tests conducted at 900°C for 24 h in 1 atm oxygen environment demonstrate significantly enhanced oxidation resistance in the NiCrAl/1 wt % TiC composite compared to the monolithic alloy. This improvement is attributed to the formation of a dual-phase oxide scale consisting of Cr 2 O 3 and TiO 2 , which replacing the porous Cr 2 O 3 layer observed on the NiCrAl alloy. The incorporation of TiO 2 promotes defect healing within the oxide film, thereby inhibiting cationic outward diffusion and oxygen inward penetration.