Investigation of the effects of an intense pulsed ion beam on the surface melting of IN718 superalloy prepared with selective laser melting

Intense pulsed ion beam irradiation on IN718 superalloy prepared with selective laser melting as an after-treatment for surface melting is introduced. It is demonstrated that intense pulsed ion beam composed of protons and carbon ions, with a maximum current density of 200 A/cm² and a pulse length of 80 ns, can induce surface melting and the surface roughness changes significantly due to the generation of micro-defects and the flow of the molten surface. Irradiation experiments and thermal field simulation revealed that the energy density of the ion beam plays a predominant role in the irradiation effect—with low energy density, the flow of molten surface is too weak to smooth the fluctuations on the surface. With high energy density, the surface can be effectively melted and smoothened while micro-defects, such as craters, may be generated and can be flattened by an increased number of pulses. The research verified that for the surface melting with intense pulsed ion beam (IPIB), higher energy density should be used for stronger surface fluidity and a greater pulse number is also required for the curing of surface micro-defects.