What Are Alloys ?How And Why Are They Prepared ?

A solid solution of two or more metals or metals and a non-metal is called an alloy. It is a homogenous mixture of two or more metals. Some alloys also contain carbon and silicon. The physical properties of alloys are generally different from their component elements.
Preparations Of alloys :
An alloy is usually prepared by melting the component element together and solidifying the mixture . The components of an alloy must be soluble in each other in the molten state. The percentage composition of the component elements may vary according to the quality of alloy desired. The component elements do not undergo any chemical changes during the process of alloying.

During preparation of alloys, following objects must be in view:
1) To modify color, e.g the color of copper is changed by additions of tin in varabile amounts.
2) To increase the elasticity , tensile strength and toughness.
3) To get good castings.
4) To modify electrical properties. The magnetic properties of alloys are different from their component elements.
5) To modify chemical reactivity. The chemical reactivity may increase or decrease by alloying . Alloys are more stable and are less affected by air and water.
6) To make metal more resistant to corrosion.