On nanograin rotation by dislocation climb in nanocrystalline materials

A theoretical model has been developed for nanograin rotation that could be achieved through dislocation climb. The results obtained show that the occurrence of nanograin rotation and the coalescence of grains depend on the external stress level, structure of grain boundary and grain size. Moreover, a critical misorientation parameter that represents the crossover between nanograin rotation and shear-coupled migration of grain boundaries has also been found, based on which a coupling mechanism between nanograin rotation and shear-coupled migration was proposed.