Spontaneous aging of a supersaturated solid solution at room temperature. See also aging. Compare with artificial aging.

The ratio, expressed as a percentage, of the amount of water vapor present in a given volume of air at a given temperature to the amount required to saturate the air at that temperature.

A metal having an extremely high melting point, for example, tungsten, molybdenum, tantalum, niobium, chromium, vanadium, and rhenium. In the broad sense, this term refers to metals having melting points above the range for iron, cobalt, and nickel.

In tensile testing, the ratio of maximum load to original cross-sectional area. Also called ultimate tensile strength.

Catastrophic brittle failure of a normally ductile metal when in contact with a liquid metal and subsequently stressed in tension.

An individual crystal in a polycrystalline metal or alloy; it may or may not contain twinned regions and subgrains; a portion of a solid metal (usually a fraction of an inch in size), in which the atoms are arranged in an orderly pattern.

Corrosion due to the action of "local cells," that is, galvanic cells resulting from inhomogeneities between adjacent areas on a metal surface exposed to an electrolyte.

A surface-active agent; usually an organic compound whose moleculei contain a hydrophilic group at one end and a lipophilic group at the other.

Deterioration of wood in contact with iron-based alloys.

A metal that readily combines with oxygen at elevated temperatures to form very stable oxides, for example, titanium, zirconium, and beryllium. Reactive metals may also become embrittled by the interstitial absorption of oxygen, hydrogen, and nitrogen.

Substance formed as a result of corrosion

The structure of a prepared surface of a metal as revealed by a microscope at a magnification exceeding 25x.

Corrosion at discrete sites, stress-corrosion cracking.

Deforming metal plastically at sucha temperature and strain rate that recrystallization takes place simultaneously with the deformation, thus avoiding any strain hardening.Contrast with c old ii orking.

The reversible interchange of ions between a liquid and solid, with no substantial structural changes in the solid.

A protective or decorative nonmetallic coating produced in silo by chemical reaction of a metal with a chosen environment. It is often used to prepare the surface prior to the application of an organic coating.

Visible at magnifications above 25x.

A nonpolarizable electrode with a known and highly reproducible potential used for potentiometric and voltammetric analyses. See also calomel electrode.

A form of high-temperature corrosion of chromium-bearing alloys in which green chromium oxide (Cr2O3) forms, but certain other alloy constituents remain metallic; some simultaneous carburization is sometimes observed.

See transgranular cracking.