Effect of Grain Boundary Migration on Fracture Toughness of Nanocrystalline Materials


A model is suggested that describes the effect of grain boundary (GB) migration on crack propagation in deformed nanocrystalline materials. Within the model, GB migration occurs under the action of high shear stresses acting near crack tips and is accompanied by the formation of the quadrupoles of wedge disclinations. It is shown that GB migration hinders crack growth and thus increases the fracture toughness of deformed nanocrystalline materials.