Nanoindentation study of mechanical and wear properties of spark plasma sintered Ti-6Ni-xTiCN composites. Issue 2 (15th January 2023) - Rominiyi, Azeez Lawan
Abstract: In this study, monolithic pure Ti and Ti-6Ni-xTiCN composites were fabricated by the spark plasma sintering method and the mechanical and anti-wear characteristics of the fabricated samples were investigated using the nanoindentation technique. Microstructural and phase analysis of the sintered samples showed the predominance of the α-Ti phase in the unreinforced pure Ti matrix. In addition to the α-Ti phase, in-situ TiN, Ti2 Ni intermetallic, and undissolved TiCN phases were detected in the matrix of the composites. Nanoindentation results revealed that the hardness (H), elastic modulus (E r ) and elastic recovery index ( W e / W t ) of the investigated samples increase with increasing reinforcement contents under varying loads of 50 mN, 100 mN and 150 mN. The nanomechanical and anti-wear properties of the analysed samples indicated dependency on the applied indentation load. The Ti-6Ni-xTiCN composites displayed higher H / E r, H 3 / E r 2 and W e / W t ratios that signified better wear and impact resistance than the unreinforced pure Ti. Microstructural integrity, which ensures consistency between the anti-wear characteristics obtained through the nanoindentation technique and the conventional wear testing, was achieved in composites containing TiCN nanoceramic contents up to 10 wt%. Ti-6Ni-10TiCN composite displayed the optimum combination of the nanomechanical and anti-wear properties across the applied loads.