Tribo–Driven Evolution of Specific Nano–heterostructures to Achieve Exceptional Wear Resistance in Composites

Abstract The study of the evolution of nano–heterostructures controlling tribological behavior is crucial for optimizing the wear resistance of composites. A novel NiAlTa/cBN composite produced by spark plasma sintering exhibited exceptional wear resistance, which is attributed to the tribo–layers with special nano–heterostructures induced by stress and temperature. At room temperature, an extremely low wear rate (10–7 mm3·N–1·m–1) and a low coefficient of friction (0.252) of the composite were attributed to the nanoscale amorphous tribo–layer. Amorphization was synergistically controlled by the plastic deformation–induced solid–state amorphization and oxidation processes. Tribo–induced amorphous layer accommodated the sliding–induced elastic–plastic deformation and virtually eliminated wear. At high temperatures, the plastic incompatibility and strain localization of the subsurface nanocrystalline layer mediated by dislocations, stacking faults, and deformation twins increased the wear rate. The formation of an amorphous tribo–oxide layer and oxidative cleaving effect reduced the fracture toughness of cBN particles and increased the tendency of crack nucleation and growth. Dislocations, stacking fault networks, and FCC → HCP phase transition synergistically increased the microplastic deformability and strain–hardening capacity of cBN particles and reduced the wear rate. Ta3N5 nanoparticles generated by tribo–chemical reaction played a load–supporting and stress–transferring role in sliding wear. This work highlighted the significance of the tribo–induced evolution of the tribo–layers on the wear resistance of the composite. A strategy to achieve exceptional wear resistance by regulating the evolution of specific nano–heterostructures on the composite surfaces was proposed.