The Shape of the Moving Grain Boundary in the Reversed-Capillary Technique Under Consideration of the Drag Effect

The shape of the curved part of the migrating grain boundary driven by capillary forces was studied for the reversed-capillary bicrystal technique. A comparison of experimentally observed and theoretically calculated shapes showed good agreement when the drag effect by mobile obstacles was taken into account. So far previous studies dealing with the reversed-capillary technique have not considered the drag effect. Consequently, they assume a scaling behavior of the shape of the moving grain boundary. In this study it is shown that this assumption generally is not possible for the reversed-capillary technique. Furthermore, it is shown that the geometry factor used for determination of the driving force is dependent on the displacement. Problems specific to the reversed-capillary technique due to the drag effect are discussed. The analysis of the boundary shape is presented as a tool to distinguish free and dragged motion.