Skip to content


Your cart is empty

Article: Alloy


Definition and Classification of Alloys

  • An alloy is a mixture of chemical elements, with at least one being a metal.
  • Alloys retain the properties of metals, such as electrical conductivity and luster.
  • Alloys may have different properties than the pure metals, such as increased strength or hardness.
  • Some alloys can reduce the overall cost of a material while preserving important properties.
  • Metallic bonding joins the atoms in an alloy, unlike covalent bonds found in chemical compounds.
  • Alloys are classified as substitutional or interstitial, based on the atomic arrangement.
  • They can be homogeneous (single phase) or heterogeneous (multiple phases).
  • Alloys can be solid solutions of metal elements or mixtures of metallic phases.
  • The constituents of alloys are measured by mass percentage or atomic fraction.
  • Intermetallic alloys have a specific atomic arrangement and properties.

Examples and Applications of Alloys

  • Red gold (gold and copper) and white gold (gold and silver) are examples of alloys.
  • Sterling silver is an alloy of silver and copper.
  • Steel and silicon steel are alloys of iron with carbon or silicon, respectively.
  • Solder, brass, pewter, duralumin, bronze, and amalgams are also alloys.
  • Alloys like beryllium-copper are used for non-sparking tools.
  • Steel alloys are used in buildings, automobiles, and surgical tools.
  • Titanium alloys are used in the aerospace industry.
  • Beryllium-copper alloys are used for non-sparking tools.
  • Alloys like duralumin find applications in the aviation industry.
  • Exotic alloys like Inconel are used in high-temperature environments.

Alloy Formation, Impurities, and Properties

  • Alloys are formed by mixing two or more elements, with one being a metal.
  • The mechanical properties of alloys can be different from their individual constituents.
  • Some alloys form solid solutions, while others have a heterogeneous microstructure.
  • Impurities in alloys can have detrimental effects on their properties.
  • Care is taken during alloying to remove excess impurities using various methods.
  • Alloys are strong solvents that can dissolve most metals and elements.
  • They readily absorb gases like oxygen and can burn in the presence of nitrogen.
  • Alloys must be melted in vacuum induction-heating and special, water-cooled, copper crucibles to avoid contamination.
  • Alloying can be done with one or more constituents in a gaseous state or in the solid state.
  • By adding another element to a metal, internal stresses are created in the lattice of metallic crystals, enhancing its properties.

Alloying Elements and Heat Treatment

  • Alloying elements are added to a base metal to induce desired properties.
  • Most metals and alloys can be work hardened by creating defects in their crystal structure.
  • Alloys can have their properties altered by heat treatment.
  • Many alloys of aluminum, copper, magnesium, titanium, and nickel can be strengthened by heat treatment.
  • Steel undergoes a change in the arrangement of its atoms when alloyed with carbon.
  • Allotropes of iron, such as alpha iron and gamma iron, show differences in atomic arrangement.
  • Alloying elements can be dissolved in iron, forming a homogeneous phase called austenite.
  • Slow cooling of steel allows carbon atoms to precipitate out, forming cementite and ferrite phases.
  • Rapid cooling of steel traps carbon atoms within iron crystals, forming a hard but brittle phase called martensite.
  • Precipitation hardening alloys soften when quenched and then harden over time.

History and Examples of Alloys

  • Alloys have been used by humans since ancient times.
  • The use of alloys started with meteoric iron, a naturally occurring alloy of nickel and iron.
  • Bronze and brass are examples of substitutional alloys.
  • Steel is an example of an interstitial alloy.
  • Stainless steel is a combination of interstitial and substitutional alloys.
  • Meteoric iron was used to make tools, weapons, and nails.
  • Bronze is an alloy of copper and tin, while brass is an alloy of copper and zinc.
  • Amalgams are alloys in a soft paste or liquid form at ambient temperature.
  • Gold was often alloyed with copper or iron for aesthetic purposes.
  • Pewter is an alloy primarily consisting of tin.

Alloy Data Sources

Reference URL
Knowledge Graph

Read more


General Information about Almandine Belongs to the garnet group Name derived from alabandicus, used by Pliny the Elder Iron alumina garnet with deep red to purple color Often cut with a convex face...

Read more

Allotropes of carbon

Allotropes of Carbon Atomic carbon can be formed by vaporizing graphite or by passing large electric currents to form a carbon arc under very low pressure. It is extremely reactive and used in the ...

Read more