Improved wear resistance of Ti-6Al-4 V alloy by fabricating a SiC/Co composite layer through ultrasonic strengthening grinding process

• A novel ultrasonic strengthening grinding process fabricates a wear-resistant SiC/Co composite coating on Ti-6Al-4 V. • The optimal treatment achieves an 88.5 % reduction in wear volume under a 10 N load. • Gradient subsurface strengthening with nano-twins and phase transformation is key to performance. • The load-dependent failure mechanism, linked to coating delamination, defines the effective service window. Ti6Al4V alloys has played a significant role in many applications owing to their low density, high strength, good corrosion resistance and high-temperature stability. However, they are suffered from relatively low hardness and poor wear resistance. To improve the wear performance, this study proposes an ultrasonic strengthening grinding process (UGSP) that incorporates selflubricating SiC ceramic powder and highhardness Co metal powder to in situ fabricate a SiC/Co composite coating on the Ti6Al4V surface. The wear resistance of the samples was systematically investigated following surface treatments with duration of 0, 4, 6, and 8 min. As a result, the sample treated for 6 min exhibited the best wear resistance across all the samples. Particularly, under a 10 N load, with a friction coefficient of 0.537 and a wear volume of only 5.93 × 10⁶ μm³, representing an 88.5 % reduction compared to the untreated sample. The enhanced wear resistance is attributed to the synergistic effect of a surface microtextured SiC/Co coating and a subsurface gradientstrengthened structure, which includes grain refinement, high dislocation density, nanotwins, elevated strain, and αtoβ phase transformation. This work provides a cheap and an efficient method for improving the wear resistance of metals.