Abstract
This study examined how ultrasonic nanocrystalline surface modification (UNSM) influences the formation of nitride layers in Ti-6Al-4V alloy during ion-plasma nitriding (IPN). We systematically varied UNSM parameters-specifically vibration amplitude, static load, and processing temperature-to assess their impact on the material's microstructure, hardness, elastic modulus, and tribological behavior. Our findings indicate that an optimized UNSM pre-treatment significantly boosts nitrogen diffusion, resulting in the creation of dense and uniform TiN/Ti₂N layers. Notably, samples subjected to UNSM under high-load and elevated-temperature conditions showed the most substantial improvements. These included a surface hardness increase of up to 25%, an elastic modulus rise of up to 18%, and enhanced wear resistance with a more stable and reduced friction coefficient (around 0.55). Further scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses corroborated these results by confirming microstructural densification, grain refinement, and a heightened intensity of nitride phases. These findings underscore the scientific value and practical applicability of UNSM as an effective surface activation method. Consequently, the hybrid UNSM + IPN approach emerges as a promising strategy for prolonging the service life of critical load-bearing components like biomedical implants and other engineering parts exposed to severe wear.