The coating, usually green, that forms on the surface of metals such as copper and copper alloys exposed to the atmosphere. Also used to describe the appearance of a weathered surface of any metal.

Provisional value for plane-strain fracture toughness.

(1) An iron mineral crystallizing in therhombohedral system; the most important oreof iron. (2) An iron oxide, Fe,O,, corrcsponding to an iron content of approximately 70%.

A chromate conversion coating produced on magnesium alloys in a boiling solution of sodium dichromate.

The lowest value of oxidizing potential at which pits nucleate and grow. It is dependent on the test method used.

A change in dimensions directly proportional to and in phase with an increase or decrease in applied force.

The property of a material by virtue of which deformation caused by stress disappears upon removal of the stress. A perfectly elastic body completely recovers its original shape and dimensions after release of stress.

Deforming metal plastically under conditions of temperature and strain rote that induce strain hardening. Usually, hut not necessarily, conducted at room temperature. Contrast with hot working.

A linear imperfection in a crystalline array of atoms. Two basic types are recognized: (1) an edge dislocation corresponds to the row of mismatched atoms along the edge formed by an extra, partial plane of atoms within the body of a crystal; (2) a screw d ...

See principal stress (normal).

Plating with dummy cathodes.

A generic term for microstructures formed by diffusionless phase transformation in which the parent and product phases have a specific crystallographic relationship. Martensite is characterized by an acicular pattern in the microstructure in both ferrous ...

Corrosion occurring under or around a discontinuous deposit on a metallic surface. Also called poultice corrosion.

A strongly alkaline solution into which metal is immersed for etching. for neutralizing acid, or for removing organic materials such as greases or paints.

Imparting resistance to oxidation to an iron or steel surface by heating in aluminum powder at 800 to 1000

The selective leaching or corrosion of a specific constituent (Al, Ni, Mo, Ni) from an alloy.

A term generally applied to paints to describe holidays, holes, and skips in a film. Also used to describe shrinkage in castings and weld.

The fracture toughness determined under dynamic loading conditions; it is used as an approximation of KIc for very tough materials.

The minimum value of Kc for any given material and condition, which is attained when rapid crack propagation in the opening mode is governed by plane-strain conditions.

In a cathodic protection system, in electrically nonconductive material, such as a coating, plastic sheet or pipe that is placed between an anode and an adjacent cathode to avoid current wastage and to improve current distribution, usually on the cathode.