Numerical investigation of the change of dislocation density and microhardness in surface layer of iron targets under the high power ion- and electron-beam treatment

The effect of the Low Energy High Current Pulsed Electron Beam (LEHCPEB) and High Power Pulsed Ion Beam (HPPIB) surface treatment on the dislocation density in iron target has been numerically investigated. At typical technological irradiation parameters the major factors for modification of dislocation density are the thermo-stresses in the heat affected zone. Irradiation regimes, within the process of which there is no melting, generate one maximum of dislocation density, at the same time the regimes resulting in melting produce two maximums of dislocation density: one of them is localized inside the layer which has crystallized from melt, and the other one at the melt–solid interface. The increase of enclosed energy density and the reduction of pulse duration make the excited stress wave even more significant for the dislocation modification. This wave causes hardening of the material in deeper layers which may eventually result in the influence on the whole volume of the target.