Correlation of microstructure with hardness and wear resistance of carbide-reinforced ferrous surface composites fabricated by high-energy electron-beam irradiation

Abstract

The present study is concerned with the correlation of microstructure with hardness and wear resistance in carbide-reinforced ferrous surface composites fabricated by high-energy electron-beam irradiation. Three kinds of powder mixtures, 50TiC-50MgF(2) (flux), 50Cr(3)C(2)-50MgF(2), and 25TiC-25Cr(3)C(2)-50MgF(2) (wt pct), were placed on a plain carbon steel substrate, which was then irradiated with electron beam. In the specimens fabricated with flux powders, the surface composite layer of about 3 mm in thickness was successfully formed without defects and contained a large amount (up to 11 vol pct) of TiC or Cr7C3 in the matrix. The hardness and wear resistance of the surface composite layer were directly increased by the hard carbides up to a maximum of 10 times with respect to the bare steel substrate. Particularly in the surface composite fabricated with TiC and Cr3C2 powders, the wear resistance was the highest because of the highest total carbide volume fraction and the matrix hardness.