Enhancing microstructure, nanomechanical and anti-wear characteristics of spark plasma sintered Ti6Al4V alloy via nickel-silicon carbide addition

Abstract

This study examines the nanomechanical and anti-wear behaviour of spark plasma sintered Ti6Al4V matrix composites reinforced with Ni and SiC particles. Microstructural analysis revealed the in-situ formation of the hard TiC, Ti₃SiC₂ and Ti₅Si₃ phases within the metal matrix. Nanoindentation analysis revealed that the composite containing 10 wt% SiC (TNi10SiC) exhibited significantly higher nanohardness (about 10.3 GPa) and elastic modulus (∼177.7 GPa) than the unreinforced Ti6Al4V alloy (sample T). The improved nanomechanical performance of the composites was attributed to the load-carrying capacity of the hard, in-situ formed reinforcement phases. The anti-wear characteristics of the composites showed that TNi5SiC composite displayed superior wear resistance with a specific wear rate of 4.75 ± 0.34 × 10⁻⁴ mm³/Nm and 2.15 ± 0.34 × 10⁻⁴ mm³/Nm under an applied loads of 10 N and 20 N, respectively, among the sintered samples. This represents about 67% and 29% reduction in specific wear rate relative to sample T. This enhanced tribological behaviour was ascribed to the increased surface hardness, the formation of a stable transfer layer, and the reduction in direct asperity contact at the sliding interfaces. However, reinforcement pull-out aggravates abrasive wear and leads to a higher specific wear rate for TNi10SiC composite. This work provides valuable information for advancing Ti6Al4V-based composites for enhanced structural and wear-resistant applications.