Effect of “surface” triple junction on curved boundary motion in Al-bicrystals

Abstract The motion of a curved grain boundary with a “surface triple junction” (“free surface–boundary–free surface”) in bicrystals is considered. The migration of a 37.5°, 39.9° and 40.6° 〈1 1 1〉 grain boundary with such a junction was measured experimentally. The effect of the “surface triple junction” on grain boundary motion is discussed in the terms of the dynamic equilibrium of boundary and junction velocity. Boundary motion in samples with different boundary curvature revealed a strict proportionality of boundary velocity and driving force. This result substantiates that in the entire investigated temperature range the “surface” triple junction does not affect the boundary motion.