MSE Rest of Vocab for final

ceramic matrix composite (CMC)

A composite for which both matrix and dispersed phases are ceramic materials. The dispersed phase is normally added to improve fracture toughness.

concrete

A composite material consisting of aggregate particles bound together in a solid body by a cement.

dispersed phase

For composites and some two-phase alloys, the discontinuous phase surrounded by the matrix phase.

fiber

Any polymer, metal, or ceramic that has been drawn into a long and thin filament.

fiber reinforced composite

A composite in which the dispersed phase is in the form of a fiber (i.e., a filament that has a large length-to-diameter ratio).

large particle composite

A type of a particle-reinforced composite in which particle-matrix interactions cannot be treated on an atomic level; the particles reinforce the matrix phase.

longitudinal direction

The lengthwise dimension. For a rod or fiber, in the direction of the long axis.

matrix phase

The phase in a composite or two-phase alloy microstructure that is continuous or completely surrounds the other ( or dispersed ) phase.

metal matrix composite

A composite material that has a metal or metal alloy as the matrix phase. The dispersed phase may be particulates, fibers, or whiskers, which normally are stiffer, stronger, and/ or harder than the matrix.

rule of mixtures

The properties of a multiphase alloy or composite material are a weighted average (usually on the basis of volume) of the properties of the individual constituents.

specific modulus (specific stiffness)

The ratio of elastic modulus to specific gravity for a material.

specific strength

The ratio of tensile strength to specific gravity for a material.

transverse direction

A direction that crosses (usually perpendicularly) the longitudinal or lengthwise direction.

anode

The electrode in an electrochemical cell or galvanic couple that experiences oxidation, or gives up electrons.

cathode

The electrode in an electrochemical cell or galvanic couple at which a reduction reaction occurs; thus the electrode that receives electrons from a external circuit.

corrosion

Deteriorative loss of a metal as a result of dissolution environmental reactions.

electrolyte

A solution through which an electric current may be carried by the motion of ions.

electromotive force (EMF) series

A ranking of metallic elements according to their standard electrochemical cell potentials.

galvanic series

A ranking of metals and alloys as to their relative electrochemical reactivity in seawater.

oxidation

The removal of one or more electrons from an atom, ion, or molecule.

reduction

The addition of one or more electrons to an atom, ion, or molecule.

standard half cell

An electrochemical cell consisting of a pure metal immersed in a 1 M aqueous solution of its ions, which is electrically coupled to the standard hydrogen electrode.

conduction band

For electrical insulators and semiconductors, the lowest-lying electron energy band that is empty of electrons at 0 K. Conduction electrons are those that have been excited to states within this band.

doping

The intentional alloying of semiconducting materials with controlled concentrations of donor or acceptor impurities.

electrical conductivity

The proportionality constant between current density and applied electric field; also, a measure of the ease with which a material is capable of conducting an electric current.

energy band gap

For semiconductors and insulators, the energies that lie between the valence and conduction bands; for intrinsic materials, electrons are forbidden to have energies within this range.

extrinsic semiconductor

A semiconducting material for which the electrical behavior is determined by impurities.

free electron

A thermodynamic quantity that is a function of both the internal energy and entropy (or randomness) of a system. At equilibrium, the free energy is at a minimum.

hole (electron)

For semiconductors and insulators, a vacant electron state in the valence band that behaves as a positive charge carrier in an electric field.

intrinsic semiconductor

A semiconductor material for which the electrical behavior is characteristic of the pure material - that is, in which electrical conductivity depends only on temperature and the band gap energy.

mobility (electron and hole)

The proportionality constant between the carrier drift velocity and applied electric field; also, a measure of the ease of charge carrier motion.

valence band

For solid materials, the electron energy band that contains the valence electrons.

heat capacity

The quantity of heat required to produce a unit temperature rise per mole of material.

linear coefficient of thermal expansion

The fractional change in length divided by the change in temperature.

specific heat

The heat capacity per unit mass of material.

thermal conductivity

For steady-state heat flow, the proportionality constant between the heat flux and the temperature gradient. Also, a parameter characterizing the ability of a material to conduct heat.

thermal shock

The fracture of a brittle material as a result of stresses introduced by a rapid temperature change.