Deformation

Deformation is the change in dimensions or forms of material under the action of applied forces. 

Metals are aggregates of crystals or grains. The characteristics of a metal depend upon the properties of crystals or grains. 

Within each grain the atoms may be imagined as packed together in a regular geometric pattern (called space lattice) which is repeated indefinitely in three dimensions to build up the solid grains. 

Because of the regular pattern of atoms they can be considered to lie in various parallel planes.

The deformation of metals is necessary to form various types of shapes without rupture. 

Deformation is based on type of strain produced due to loading of metal. 

The resistance of a crystalline body to deformation is dependent upon the bonding forces between the atoms. 

There are mainly two types of deformations such as elastic & plastic deformation. 

Elastic Deformation: When force is applied on the metal within a limit, atoms move along the direction of force and occupy the new position, but on the removal of force, the atoms come back to their original position is called elastic limit and this type of deformation is called elastic deformation.

Plastic Deformation: When force is applied on the metal beyond the elastic limit, atoms does not come back to their original position on removal of applied force and occupy the new position. This type of deformation is called plastic deformation.