Surface Stress Characteristics in Pure Nickel after High Current Pulsed Electron Beam Irradiation

Polycrystalline nickel samples were irradiated with high-current pulsed electron beam (HCPEB). The induced deformation structures were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The relationship between the stress characteristics induced by HCPEB irradiation and the deformation structures was established, and the current numerical simulation results of stress were discussed. The experimental results showed that stress with about 5 GPa had been introduced in the irradiated surface layer, which led to severe plastic deformation (e.g., twin deformation) on the irradiated surface. Both the quasi-static thermal stress and the impact stress wave that induced by plasma pulsed explosion during the HCPEB processing are the main cause of the surface microstructure changes.