A twisting deformation of a solid body about an axis in which lines that were initially parallel to the axis become helices.

Overvoltage associated with the liberation of hydrogen gas.

A loss ofstrength and ductility of .steel by high-temperature reaction of absorhcd hydrogen with carbides in the steel resulting in dec arbwri:.alien and internal fissuring.

A coating process whereby the cleaned and masked component to be coated is heated and rotated on a spindle above the streaming vapor generated by melting and evaporating a coating material source bar with a focused electron beam in an evacuated chamber.

The threshold value of the corrosion potential that has to be reached to enter a protective potential range. The term used in cathodic protection to refer to the minimum potential required to supress corrosion.

Fracture through or across the crystals or grains of a metal. Also called transcrystalline fracture or intracrystalline fracture. Contrast with intergranular fracture.

The opposition that a device or material offers to the flow of direct current, equal to the voltage drop across the element divided by the current through the element. Also called electrical resistance.

The maximum or minimum value at the normal stress at a point in a plane considered with respect to all possible orientations of the considered plane. On such principal planes the shear stress is zero. There are three principal stresses on three mutually p ...

See corrosion potential and open-circuit potential.

A scaling factor, usually denoted by the symbol K, used in linear-elastic fracture mechanics to describe the intensification of applied stress at the tip of a crack of known size and shape. At the onset of rapid crack propagation in any structure containi ...

Hardening caused by the precipitation of a constituent from a supersaturated solid solution. See also age hardening and aging.

The time rate of straining for the usual tensile test. Strain as measured directly on the specimen gage length is used for determining strain rate. Because strain is dimensionless, the units of strain rate are reciprocal time.

Any of various functions from which intensity or velocity at any point in a field may be calculated. The driving influence of an electrochemical reaction. See also active potential, chemical potential, corrosion potential, critical pitting potential, deco ...

The rate of charge transfer per unit area when an electrode reaches dynamic equilibrium (at its reversible potential) in a solution; that is, the rate of anodic charge transfer (oxidation) balances the rate of cathodic charge transfer (reduction).

Lacking an affinity for, repelling, orfailing to absorb or adsorb water. Contrast with hydrophilic.

Same as intergranular corrosion. See also interdendritic corrosion.

A general term for the emhrittlement, cracking, blistering. and hydride formation that can occur when hydrogen is present in some metals.

Factor for a loading condition that displaced the crack faces in a direction normal to the crack plane (also known as the opening mode of deformation).

(1) The change from the open-circuit electrode potential as the result of the passage of current. (2) A change in the potential of an electrode during electrolysis, such that the potential of an anode becomes more noble, and that of a cathode more active, ...

The reversible potential for an electrode process when all products and reactions are at unit activity on a scale in which the potential for the standard hydrogen half-cell is zero.