Increasing Thermal Stability of the Surface of Submicrocrystalline Nickel under High-Fluence Ion Irradiation

-The results of an experimental study of the effect of high-fluence ion irradiation on the thermal stability of the microstructure and surface relief of submicrocrystalline nickel are presented and discussed. The submicron structure of nickel is obtained during severe plastic deformation by torsion under a high pressure of 6 GPa. Irradiation with 30-keV argon ions with a dose of 3 x 10(18) cm(-2) is carried out. The ion irradiation of submicrocrystalline nickel is shown to lead to the formation of a cone-shaped surface morphology. This morphology is thermally stable up to a temperature of at least 500 degrees C. Using etching with a focused 30-keV gallium-ion beam, a surface layer 10-mu m thick of irradiated submicrocrystalline nickel annealed at 500 degrees C is studied. It is found that the ion-induced cone-shaped morphology of the surface could be preserved during annealing and block grain growth in the surface layer.