The resistance of a materiel to elastic deformation is called stiffness.
Whenever an external force is applied on a metal, it deforms. Elasticity is the property by virtue of which a metal regains its original shape when the external force applied on it is removed.
es: forming, forging, hammering
Ductility: Ductility is the property by which a metal can be drawn into thin wires. It is determined by percentage elongation and percentage reduction in area of a metal.
Malleability: Malleability is the property by which a metal can be rolled into thin sheets. Highly malleable metals (like Mild Steel) are extensively used in making sheet metals.
Stiffness: When an external force is applied on a metal, it develops an internal resistance. The internal resistance developed per unit area is called stress. Stiffness is the ability of a metal to resist deformation under stress.