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Metal deformation Introduction The changes in shape of metal piece under the action of a single force or set of forces os known as deformation or mechanical deformation. Classification of metal deformation 1. Elastic deformation 2. Plastic deformation Elastic deformation The term elastic deformation may be defined as the process of deformation, which appears and disappears simultaneously with the application and removal of stress. It has been observed that whenever a stress of low magnitude is applied to a piece of metal it causes displacement of atoms from their original positions But on the removal of stress, the atoms spring back and occupy their original positions.          Plastic deformation The term plastic deformation may be defined as the process of permanent deformation, which exist in a metal, even after the removal of the stress. Example- Rolling, Forging, Drawing, spinning The plastic deformation in crystalline materials occurs at temperature lower than 0.4 Tm (Tm is the m

Mechanical properties of metals Following mechanical properties is important. 1. Elasticity- The term elasticity may be defined as the property of a metal by virtue of which it is able to retain its original shape after the removal of the load.In nature no material is perfectly elastic, over the entire range of stress, up to rupture. 2. Plasticity The term plasticity may be defined as the property of a metal by the virtue of which a permanent deformation (without fracture) take place, whenever it is subjected to the action of external forces.The plasticity of metal depends upon its nature and environmental condition. 3. Ductility- The term ductility may be defined as the property of metal by virtue of which it can be drawn into wires or elongated before rupture takes place. it depends upon grain size of the metal crystal. 4. Percentage elongation- The term percentage elongation is the maximum increase in the length expressed as percentag