Inverse Kirkendall mixing in collision cascades

We study ion-beam mixing of metallic bilayer interfaces using classical molecular-dynamics simulations of 5 keV collision cascades in the vicinity of Co/Cu and Ni/Cu (111) interfaces. We find that the production of vacancies and interface roughening is asymmetrical. On average, more Cu is introduced into the Co or Ti pal ts than vice versa, and more vacancies are produced in the Ca, indicative of an inverse Kirkendall effect in collision cascades. The effect is explained by the difference in melting points leading to different recrystallization rates of the two materials, [S0163-1829(99)11601-1].