Plasticity:
Plasticity is the property by which a metal retains its deformation permanently, when the external force applied on it is removed.
Examples: 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.
Brittleness
Brittleness is a property of material which breaks with little or no deformation.