Engineering materials can be classified as metallic materials and non-metallic materials, depending on whether or not they posses the well defined metallic characteristics. The class of metallic materials includes metals and alloys.
Metallic materials can further be classified as ferrous and non-ferrous. Ferrous materials include steel, cast irons and wrought iron. Non-ferrous materials include all other metals such as Cu, Al, Ni, Zn, Ti, Mg, etc. and their alloys. The non-metallic materials include ceramics and glasses and polymers. Examples of non-metallic materials are wood, concrete, cement, bricks, stone, ceramics, plastics, rubber, leather, etc.
The advancement in technology has created a new class of materials called composites. Some typical examples include glass fibre reinforced plastic (GRP), Thoria dispersed nickel (TD-nickel), sintered aluminium powder/product (SAP) and cermets. Though metallic materials still play the most important and significant role in industries, non-metallic materials have also assumed vital importance in recent years and compete with metallic materials, in particular for applications requiring weight saving and chemical inertness. Figure 1.1 is a flow chart showing the classification of engineering materials.