Generally, engineering materials are classified into four types viz. Metals and alloys, ceramics and glasses, polymers, and composites. Let’s have a look at them.
|Classification of Engineering Materials|
Table of Contents
Classification of Engineering Materials
- Metals and Alloys
- Ceramics and glasses
Metals and Alloys
Inorganic materials are composed of one or more metallic elements.
- They usually have crystalline structures and are good thermal and electrical conductors.
- They maintain their good strength at high and low temperatures.
- Many metals have high elastic strength and high elastic modulus.
- They are the least resistant to corrosion.
- They have sufficient ductility.
- One more important characteristic, they can be strengthened by alloying and heat treatment.
Ceramics and Glasses
Inorganic materials consisting of both metallic and non-metallic materials bonded together chemically.
- They can be crystalline (ceramics), non-crystalline (glasses), or a mixture of both (glasses and ceramics).
- They have high hardness, high moduli, and high-temperature strength.
- Since they are brittle, they cannot be used as good as metals.
- Generally, they have a high melting point and high chemical stability.
- Ceramics are generally poor conductors of electricity.
- Ceramics have high strength on compression.
Organic materials consist of long molecular chains or networks containing carbon.
- They generally have low densities and low rigidity.
- Their mechanical properties may vary considerably.
- Most polymers are non-crystalline but some consist of a mixture of both crystalline and non-crystalline regions.
- Most of them are corrosion resistant, but they cannot be used at high temperatures.
- Most of them are poor conductors of electricity due to the nature of atomic bonding.
- They generally have good strength to weight ratio.
Materials where two or more of the above materials are brought together on a macroscopic level.
- They are designed to combine the best properties of each of its components.
- Usually, they consist of a matrix and a reinforcement.