CoachIn dislocation creep crystals deform by the glide of dislocations, with climb releasing them from obstacles. In diffusion creep they change shape by the diffusion of atoms, through the lattice (Nabarro–Herring creep) or along the grain boundaries (Coble creep), from the faces under the highest normal stress to those under the lowest. In grain-boundary sliding grains slide past one another along their boundaries, the gaps being closed by diffusion or dislocation creep. In pressure solution the matter dissolves in a fluid film on the faces under high stress and is deposited where the stress is low, or carried away.
