Study of ion bombardment-induced subsurface compositional modifications in Ni-Cu alloys at elevated temperatures by ion scattering spectroscopy

Changes in the subsurface composition of Ni-40 at.% Cu alloys during 3-keV Ne+ bombardment at temperatures between 25 and 7000C were studied by means of ion scattering spectroscopy. Both the time evolution of the composition in the surface atom layer during ion bombardment and subsurface concentration profiles after rapid specimen cooling to room temperature were measured as a function of temperature. Radiation-enhanced diffusion coefficients were derived from the effective altered-layer thicknesses obtained. A comparison of the experimental measurements with theoretical calculations based on a phenomenological model enabled the identification of processes and kinetics responsible for subsurface compositional modifications