Microstructure and properties of surface modified layer for M50 steel by high current pulsed electron beam

Surface modification of M50 steel was performed by using high current pulsed electron beam with various energy density, and the surface morphology, hardness and phase composition of modified layer at different irradiated energy were studied. The results show that the surface of M50 steel is melted under irradiation and it forms defect of crater-like morphology, which leads to an increasing of roughness. The grains are refined obviously in the melted layer after irradiation. The content of retained austenite increases with the increase of the irradiation energy density, resulting the decrease of surface hardness. The corrosion resistance of the irradiated sample enhance because of solution of carbides.