Metallurgy Glossary

A material composed of two or more elements, at least one of which is a metal, combined to achieve properties not attainable by a single element.

A heat treatment process involving heating to a specific temperature, holding, and slow cooling to relieve stresses, increase ductility, and refine microstructure.

The face-centered cubic (FCC) phase of iron, stable at elevated temperatures, capable of dissolving significant amounts of carbon.

A hardness measurement obtained by pressing a hardened steel or tungsten carbide ball into the metal surface under a specified load and measuring the indentation diameter.

A manufacturing process in which molten metal is poured into a mold cavity and allowed to solidify into the desired shape.

Iron carbide (Fe3C), an intermetallic compound that is extremely hard and brittle, commonly found in steels and cast irons.

The electrochemical degradation of a metal caused by chemical reactions with its environment, most commonly oxidation in the presence of moisture.

Time-dependent plastic deformation occurring under constant stress at elevated temperatures, typically above 0.4 times the melting temperature in kelvin.

The ordered, repeating spatial arrangement of atoms in a crystalline solid, defined by the unit cell geometry.

The ability of a metal to undergo significant plastic deformation before fracture, typically measured as percent elongation or percent reduction in area.

Failure of a metal under repeated cyclic loading at stresses below the static yield strength, progressing through crack initiation, propagation, and final fracture.

The body-centered cubic (BCC) phase of iron, stable at room temperature, characterized by low carbon solubility, good ductility, and magnetic properties.

The interface region between two adjacent grains of different crystallographic orientation in a polycrystalline metal.

The ability of a steel to form martensite throughout its cross-section upon quenching, influenced by alloy composition and measured by the Jominy end-quench test.

Controlled heating and cooling operations performed on a metal in the solid state to alter its microstructure and mechanical properties.

The extraction and recovery of metals from ores using aqueous solutions through processes such as leaching, solvent extraction, and electrowinning.

A metastable, supersaturated solid solution of carbon in iron with a body-centered tetragonal structure, formed by rapid quenching of austenite. It is the hardest microstructure in steel.

A lamellar microstructure consisting of alternating layers of ferrite and cementite, formed during the slow cooling of eutectoid steel.

A graphical representation of the equilibrium relationships between phases in a material system as a function of temperature, composition, and sometimes pressure.

The extraction and refining of metals using high-temperature processes such as roasting, smelting, and converting.

The formation of new, strain-free grains in a previously cold-worked metal upon heating above a critical temperature, replacing the deformed grain structure.

A process in which compacted metal powder is heated below its melting point to bond particles through solid-state diffusion, producing a dense, strong part.

A single-phase crystalline structure in which solute atoms are dissolved in the solvent metal lattice, either substitutionally (replacing host atoms) or interstitially (fitting between host atoms).

The maximum stress a material can withstand while being stretched or pulled before breaking, measured in a uniaxial tensile test.

The stress at which a metal begins to deform plastically. Below this stress, the material deforms elastically and returns to its original shape when the load is removed.