Microstructure and properties of low carbon steel after surface alloying induced by high current pulsed electron beam

To improve the surface properties of low carbon steels, Cr alloying layer was introduced on the steel substrate irradiated by high current pulsed electron beam (HCPEB) alloying treatment. The microstructures of the Cr alloying layer were studied by means of XRD, OM, SEM and TEM. The properties of microhardness and corrosion resistance were also tested. Microstructure observations revealed that after HCPEB alloying, the surface was remelted and the thickness of the remelted layer was about 4-6 μm. The content of Cr in the remelted layer was higher than that of the matrix. TEM results revealed that the cementite in pearlite was dissolved, and a high density of dislocations and tiny reinforcing phases were formed in the alloying layer. Both of the microhardness and corrosion resistance of the irradiated samples were significantly improved after HCPEB alloying treatment.