Q. Describe Elastic and plastic deformation?

When a sufficient load is applied to a metal or other structural material, it will cause the material to change shape. This change in shape is called deformation. When the stress is sufficient to permanently deform the metal, it is called plastic deformation. Plastic deformation involves the breaking of a limited number of atomic bonds by the movement of dislocations. A slip band appears as a single line under the microscope, but it is in fact made up of closely spaced parallel slip planes.