Microstructure and hardness improvement of TiC/stainless steel surface composites fabricated by high-energy electron beam irradiation

Stainless steel-base surface composites reinforced with TiC particles were fabricated by high-energy electron beam irradiation. Three kinds of powder/flux mixtures: TiC, (Ti+C), and (Ti+SiC) powders with 40 wt.% of CaF2 flux were deposited evenly on an AISI 304 stainless steel substrate, which was then irradiated with an electron beam. TiC agglomerates of partially remelted particles and pores were found in the surface composite layer fabricated by irradiation of TiC powders. In the composite layer fabricated by irradiation of Ti and C powders having lower melting points than TiC powders, a number of primary TiC particles were precipitated without forming TiC agglomerates or pores. This indicated the more effective TiC precipitation obtained from the melting of Ti and C powders, instead of TiC powders. The hardness and wear resistance of the surface composite layer were directly affected by the hard primary TiC particles, and thus were two to three times greater than those of the stainless steel substrate.