Low angle tilt boundary migration coupled to shear deformation

The shear stress induced migration of planar 〈1 0 0〉 tilt grain boundaries in Al bicrystals was observed to be perfectly coupled to the lateral translation of grains. Boundaries with misorientations of 10.5° and 12.0° on one side of the misorientation range (0–90°) and 81.0° and 81.1° on its other side move in opposite directions under the same applied external stress. The measured ratios of the normal to the lateral motion comply perfectly with the coupling factors of a recently proposed model of boundary motion.