Properties Of Engineering Materials

Engineering Materials exhibit the following properties. They are
(1.) Physical properties.
(2.) Mechanical properties.
(3.) Electrical properties.
(4.) Magnetic properties.
(5.) Chemical properties.

Physical Properties of Engineering Materials.

The physical properties of engineering materials, metals in particular are colour, size, shape, density, thermal conductivity, melting point and boiling point.

Mechanical Properties of Engineering Materials.

The mechanical properties exhibited by engineering materials include strength, elasticity,plasticity, ductility, stiffness,malleability, toughness, brittleness, hardness, fatigue and creep etc.
(1.) Strength: This is the ability of a material to resist or withstand externally applied forces to which it is subjected to during a test or in service without breaking. The internal resistance by a material to the externally applied force is called stress. The strength of a material could be defined in terms of tensile strength, compressive strength, proof stress, shear strength etc. Also the strength of any engineering material could be seen as the measure of the capacity of the resistance of solid masses or pieces of the material to any force tending to produce in them a permanent deformation or fracture. The strength of engineering materials depends on the forces which are present in and around the molecules of the material. One of these forces is cohesion. Another one is adhesion.
(2.) Elasticity: This is the property of a material to regain its original shape and size after deformation when the external load or force causing the deformation is removed. A material is said to be perfectly elastic if all the stresses (which lead to the deformation of the material) disappears completely upon the removal of the load. This property is desirable for materials used in machine cutting tools. Elasticity has a constant of proportionality called Young's Modulus (E).
(3.) Stiffness:This is the ability of a material to resist deformation under stress. The Young's Modulus (E) is a measure of the stiffness of a material.
(4.) Plasticity: This is the property of a material to remain deformed permanently or to retain a deformation caused by an applied load permanently after the removal of the load. During plastic deformation, there are displacement of atoms within the grains of the material. This makes the material to experience a change in shape.