Alloy

          A substance which is composed of two or more than two chemical elements such that metallic atoms predominates in composition and the metallic bond predominates is called an "Alloy". The element which is present in largest proportion is called "base metal" and all other elements present are known as "alloying elements".

         Alloys are classified as binary alloys, composed of two components; as ternary alloys, composed of three components; or as multicomponent alloys. Most commercial alloys are multicomponent. The composition of an alloy is described by giving the percentage (either by weight or by atoms) of each element in it.

          Metal alloys by virtue of composition, are often grouped into two classes : Ferrous and Non-Ferrous. Ferrous alloys are those in which iron is the principal constituent, include steels and cast irons. The non-ferrous alloys are all alloys that are not iron based.

          Alloys are widely used in industry because their physical and chemical properties can be easily varied to suit the exact individual requirement. One can achieve this by preparing alloys of different metals.