Diffusion of Nanobubbles in fcc Aluminum

The existing theories of diffusion of gas-filled and empty bubbles in solids as yet do not have sufficient predictive power and require refinements that can be made using simulation. The method of the accelerated molecular dynamics simulation of the bubble drift in a pressure gradient is theoretically substantiated in this work. This method is used to calculate the diffusion coefficient of empty nanobubbles in aluminum. The theory of diffusion by means of the formation of critical terraces on the faces is supplemented in such a way that there is no contradiction with the continuous model for macroscopic dimensions. The simulation results show the key role of the formation mechanism of terraces in nanobubbles and confirm the amended theory. The inclusion of the effect of gas makes it possible to compare the simulation results with experimental data. The comparison also confirms the formation mechanism of terraces.