Microstructural and Mechanical Properties of TiC, TiB₂ and VC with Low Carbon Steel Surface Alloy Fabricated by High Energy Electron Beam Irradiation

Because of its excellent process advantages such as high energy, efficiency, short irradiation time and rapid heating, high energy electron beam (HEEB) irradiation is becoming of interest as a future surface modification technology. In this study, surface alloying of TiC, TiB2 and VC ceramic particles with a low carbon steel substrate was carried out using HEEB of 1.4 MeV. Surface alloyed layers of all the specimens were about 2 min thick and consisted of a melted region, an interface region, a heat affected zone (HAZ) and the matrix. In all the specimens, the hardness at the surface was the highest, and then decreased sharply into the interior reaching the lowest values at the matrix. A remarkable increase in the mechanical properties was observed for the VC surface alloyed specimen. Vanadium carbides of large (similar to 5 mu m) and fine sizes (similar to 20 nm) were formed uniformly, which resulted in an increase of hardness to 2-3 times of that of the matrix, and highest wear resistance.