Enhancing mechanical and tribological properties of Ni3Al-15vol%TiC composite by high current pulsed electron beam irradiation

Abstract

Effects of high current pulsed electron beam irradiation (HCPEBI) on the surface microstructure, mechanical properties, room and high temperature tribological behavior of the Ni3Al-15vol%TiC composite were investigated. The HCPEBI process refines the TiC particles down to nano scale and distributes them homogeneously throughout the modified layer. It also decreases grain size of the Ni3Al down to 400 nm. Grain refinement and homogeneous distribution of the TiC nanoparticles by irradiation process increase surface hardness from 538 HV0.025 to about 728 HV0.025. The HCPEBI process increases also the wear resistance of Ni3Al-15vol%TiC composite at both room temperature and elevated temperature of 600 °C due to the increasing hardness and roughening the surface of the sample. Adhesive wear was found to be the dominant wear mechanism for both as-received and irradiated samples at room temperature beside with the delamination. At the elevated temperature of 600 °C, oxidative wear and delamination of the oxide layers occur as the main wear mechanisms in the as-received sample. In the irradiated sample, on the other hand, wear starts with the abrasive wear with micro-cutting of surface hills of irradiated sample, and continues with oxidative and delamination wear mechanisms.