The phase and microstructure changes in 45^# steel irradiated by intense pulsed ion beams

Intense pulsed ion beam (IPIB) treatment is a new technology of surface modification. Compared to traditional ion implantation, the intense pulsed energy effect takes the main role in the IPIB modification processes. Therefore, the phase and microstructure changes induced by IPIB irradiation is much stronger than those induced by traditional ion implantation. We investigated the phase and microstructure changes in surface layer of 45^# steel samples irradiated with intense pulsed ion beams at different pulsed energy densities by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The nanohardness distribution in a cross-section of the sample surface layer was also measured. The ferrite and laminated pearlite structures in near surface layer was changed in different degrees that grow with the pulsed energy density. The depths of these modified layers are much deeper than the ion range. Polished surfaces of samples were roughened with 10 μm-scale width and 1 μm-scale depth craters. The results of above analyses are discussed.