The effects of TiN nanoparticle incorporation on the microstructure and wear resistance of additively manufactured CoCrMoW alloys

To enhance the wear resistance of CoCrMoW alloys, this study used laser powder bed fusion (LPBF) to fabricate TiN nanoparticle-incorporated composites. By conducting microstructure characterization and wear resistance testing, the intricate relationship between microstructure and wear behavior was elucidated. The LPBF-fabricated samples presented dual-phase structures comprising face-centered cubic and hexagonal close-packed phases along with numerous stacking faults. The TiN particles were uniformly distributed in the sample with a 1 wt% addition. However, as the additive content increased, the TiN particles grew, and the interparticle spacing correspondingly decreased. Notably, robust interfacial bonding existed between the TiN nanoparticles and the matrix material. The interface between the TiN particles and the matrix displayed a semicoherent nature characterized by a specific orientation relationship: [001] _TiN//[011]_γ and (020)_TiN//(111)_γ. Compared to the nonincorporated sample, the incorporated samples demonstrated reduced friction coefficients and wear rates. A comparative analysis of the nonincorporated and incorporated samples’ wear behaviors revealed that oxidation wear predominantly characterized the nonincorporated sample, which displayed significant plastic deformation along with fragmented debris and loose oxides. In contrast, the incorporated samples presented relatively smooth wear surfaces where abrasive wear emerged as the primary mechanism. These findings underscore enhancements in tribological properties due to TiN incorporation and offer valuable insights into its fundamental behavior during wear.