The nucleation of atomic steps on inert gas bubbles intersected by dislocations

Abstract

The diffusivities of small polyhedral bubbles attached to dislocations in copper thin foils were calculated from observations of the distances migrated and the rate of diffusion to the foil surface during isothermal annealing. It was shown that when few collisions occur between bubbles the bubble diffusivity could be easily calculated from the experimental data. The bubble diffusivities were satisfactorily described by a rate-controlling nucleation mechanism, in which ledges introduced into the bubble surface by the dislocation rotated about the dislocation, causing the bubble to migrate. The model predicted that bubbles intersected by dislocations would have higher diffusivities than bubbles in a perfect lattice.