Laser-based Powder Bed Fusion of dispersion strengthened CoCrNi by ex-situ addition of TiN

Paper in proceeding, 2022

In this study, metal matrix composites (MMC) of a CoCrNi medium entropy alloy (MEA) reinforced with titanium nitride (TiN) nano-sized particles were designed for production by laser-based powder bed fusion (LB-PBF). Two different additions, 0.5 wt% and 5 wt% of TiN nanosized particles, were mixed with CoCrNi using tumbling and ball milling, respectively. The results suggest that although the powder morphology is not significantly affected by the TiN addition, the processability of CoCrNi-5 wt% TiN is worse than that of CoCrNi and CoCrNi-0.5 wt% TiN. The hardness of CoCrNi, originally 278 HV, is enhanced by addition of 0.5% and 5% TiN to 309 HV and 357 HV respectively. This hardening is mainly due to the presence of reinforcement particles in the matrix. The work presented here shows promising processability of MMC based on MEAs by LB-PBF, as well as the beneficial effect of the reinforcement phase on the mechanical properties of MEAs.