Improvement of hardness and wear resistance in stainless-steel-based surface composites fabricated by high-energy electron beam irradiation

Improvement of hardness and wear resistance in stainless-steel-based surface composites, fabricated by high-energy electron beam irradiation, was investigated in this study. Three kinds of powders, i.e., Cr3C2, CrB, and CrB+Cr, were placed on an AISI 316L stainless steel substrate, which was then irradiated with an electron beam. In the specimens fabricated without the flux addition, the surface composite layer of 2.0∼3.6 mm in thickness was successfully formed without defects by the self-fluxing effect and contained a large amount of hard precipitates in the austenite matrix. The composite layer fabricated with Cr3C2 powders was thicker than that fabricated with CrB powders because of more effective melting of Cr3C2 powders during electron beam irradiation. The hardness and wear resistance of the surface composite layer were directly influenced by the amount of hard precipitates and thus were about two times greater than those of the stainless steel substrate. High-temperature hardness was maintained high over 200 VHN up to 750 °C. Thus, various applications of the stainless-steel-based surface composites to the development of advanced materials with high resistance to heat and abrasion were expected.