Deformation (strain) /diːfɔːrˈmeɪʃən/ /streɪn/ – deformation of rocks – changes in the shape and volume of rocks under the influence of tectonic forces. Deformation can occur with a change in the volume of rocks when hydrostatic pressure acts, or the volume and shape of a body, or only the shape when directed forces act.
Ex. Explosive deformation may be a preliminary operation for the subsequent change of the metal’s structure by annealing.