A superhard material has high shear modulus, high bulk modulus and does not deform plastically. This movement of dislocations results in the material plastically deforming. These materials plastically deform when the bending moment exceeds the fully plastic moment. The unit is pressurized and the liner is allowed to plastically (permanently) deform. In both cases, a burnishing tool runs against the workpiece and plastically deforms its surface. Hence, whether the system behaves plastically or elastically is independent of the applied normal force. Hot working process metals are plastically deformed above their recrystallization temperature. The chewed bubble gum, on the other hand, will plastically deform enormously before finally breaking. The yield calculation will determine the safety factor until the part starts to deform plastically. This implies that the material can plastically deform, and, therefore, is tough. It is a plastically deformed diamond of type IIa, and has a clarity of VS2. Thus, the resin can be plastically formed at lower temperatures and/or with lower force. Its features and details on the face are made extremely plastically and grotesquely. Deeper in the Earth, rocks behave plastically and fold instead of faulting. Peening a surface spreads it plastically, causing changes in the mechanical properties of the surface.