Alloys are produced by melting or sintering two ore more metals, or metals and a non-metal, together.
Alloys possess typical properties inherent in the metallic state. The chemical elements that make up an
alloy are called its components. An alloy can consist of two or more components. The phase and
structures of alloys describe the constitution, transformations and properties of metals and alloys. A
combination of phases in a state of equilibrium is called a system. A phase is a homogeneous portion of
a system having the same composition and the same state of aggregation throughout its volume, and
separated from the other portions of the system by interfaces. For instance, a homogeneous pure metal
or alloy is a single-phase system. A state in which a liquid alloy (or metal) coexists with its crystals is a
two-phase system. Structure refers to the shape, size or the mutual arrangement of the corresponding
phases in metals or alloys. The structural components of an alloy are its individual portions, each having
a single structure with its characteristic features.