SINGLE-BOUNDARY RESULTS
Migration Dominated
Downloadable .avi file (6.77 MB)
This video is of a single thin film with a single grain boundary with interface migration as the only driving force. The difference in surface tension is 0.3 for the surface boundary at the top, and 0.5 for the surface boundary at the ground. The video shows the equilibrium angle of the grove form quickly as well as the angle between the grain boundary and the ground. Once these angles have formed, the grain boundary slowly moves to the right, as expected from the theoretical model of this situation. There is no increase of the film height outside of the grove because migration is the dominating force, not diffusion. This is very similar to a simple thermal-grooving case, except the grain boundary moves slowly due to the force imbalance at the bottom and top of the film. We used this as a baseline for our experiments, and built upon this code to create more complicated geometries. We were then able to compare the behavior of this simple geometry to the two layer case and the multi-grain case.
Migration and Diffusion
Downloadable .avi file (6.47 MB)
This is the same simulation as the first video, except the diffusion mechanism of evolution has been added. The surface tension values are the same for the top and bottom. The differences from the migration dominated case are very apparent from the start, as the diffused atoms form two large ridges on either side of the groove that forms immediately. Once the equilibrium angles of the groove and grain boundary have formed, the boundary slowly moves to the right from the surface tension imbalances and the driving force from the slight curvature. Also, as it moves farther to the right, the ridge on the right side of the groove becomes larger, as more atoms are forced out of the groove due to interface diffusion. This simulation yields an image very similar to the results expected from the theoretical model.