A study on microstructure and service property of Ni₃Al base alloy irradiated by intense pulsed ion beams

Ni₃Al base alloy samples, a kind of high temperature material, were irradiated with intense pulsed ion beams (IPIB) at the beam parameters of 250 KV acceleration voltage, 100-200 A/cm² current density and 60 ns pulse duration. The surface morphology and the cross-section microstructures of the samples were observed with Scanning Electron Microscope (SEM): X-ray Diffraction (XRD) method was used to determine the phase and structural changes that occured in the near surface region of the samples after IPIB irradiation. Craters with different diameters ranging from a few microns to 30 microns appeared and spread all over the irradiated surfaces. The near surface region of irradiated samples had been melted or even evaporated and then was quickly resolidified: moreover a new structural layer of approximately 4-5 μm thick was formed at 200 A/cm² IPIB irradiation. Both the wear resistance and the oxidation resistance property at high temperature environment were improved in general at the near surface region of irradiated samples. The relations between the microstructural transformations and the service property changes were reasonably discussed.