Materials Test 3

Front 1

Stress-relief Anneal

Back 1

The recovery stage of the annealing heat treatment during which residual stresses are relieved without reducing the mechanical properties

Front 2

Tempering

Back 2

Heat treatment that leads to a compressive stress on the surface of a glass. Metals-soften to increase toughness

Front 3

Chill Zone

Back 3

A region of small, randomly oriented grains that forms at the surface of a casting as a result of heterogeneous nucleation

Front 4

Dendrite

Back 4

Tree-like structure of the solid that grows when an undercooled liquid solidifies.

Front 5

Recovery

Back 5

A low-temperature annealing heat treatment designed to eliminate residual stresses introduced during deformation. without reducing strength

Front 6

Recrystallization

Back 6

A medium-temperature annealing heat treatment designed to eliminate all of the effects of strain hardening produced during cold-working

Front 7

Residual Stresses

Back 7

Stresses introduced in a material during processing.

Front 8

Strain Hardening

Back 8

Strengthening of a material by increasing the number of dislocations by deformation, or cold-working

Front 9

Annealing

Back 9

Heat treatment used to eliminate part or all of the effects of cold working. For glasses, it removes thermally induced stress

Front 10

Cold Working

Back 10

Deformation of a metal below the recrystallization temperature. Number of dislocations increase changes shape and stronger

Front 11

Frank-Read Source

Back 11

A pinned dislocation that, uder an applied stress, produces additional dislocations. Partially responsible for strain harden

Front 12

Hot Working

Back 12

Deformation of a metal above the recrystallization temperature. Shape changes, strength remains the same

Front 13

Dispersion strengthening

Back 13

Increase in strength of a metallic material by generating resistance to dislocation motion by the introduction of small clusters of a second material.

Front 14

Embryo

Back 14

A tiny particle of solid that forms from the liquid as atoms cluster together.

Front 15

Growth

Back 15

The physical process by which a new phase increases in size.

Front 16

Heterogeneous Nucleation

Back 16

Formation of critically-sized from the liquid on an impurity surface.

Front 17

Homogeneous Nucleation

Back 17

Formation of a critically-sized solid from the liquid by the clustering together of a large number of atoms at a high undercooling.

Front 18

Inoculation

Back 18

The addition of heterogeneous nuclei in a controlled manner to increase the number of grains in a casting

Front 19

Nucleation

Back 19

The physical process by which a new phase is produced in a material.

Front 20

Planar Growth

Back 20

The growth of a smooth solid-liquid interface during solidification, when no undercooling of the liquid is present.

Front 21

Thermal Arrest

Back 21

A plateau on the cooling curve during the solidification of a material caused by the evolution of the latent heat of fusion during solidification.

Front 22

Undercooling

Back 22

The temperature to which the liquid metal must cool below the equilibrium freezing temperature before nucleation occurs.

Front 23

Total Solidification Time

Back 23

The time required for the casting to solidify completely after the casting has been poured.

Front 24

Freezing Range

Back 24

The temperature difference between the liquidus and the solidus temperatures.

Front 25

Hume-Rothery Conditions

Back 25

The conditions that an alloy or ceramic system must meet if the system is to display unlimited solid solubility.

Front 26

Isomorphous phase diagram

Back 26

A phase diagram in which components display unlimited solid solubility

Front 27

Lever Law

Back 27

A technique for determining the amount of each phase in a two-phase system

Front 28

Limited Solubility

Back 28

When only a maximum amount of a solute material can be dissolved in a solvent material

Front 29

Liquidus

Back 29

Curves on a phase diagram that describe the liquidus temperatures of all possible alloys

Front 30

Phase

Back 30

Any portion, including the whole of a system, which is physically homogeneous within it and bounded by a surface so that it is mechanically separable from any other portions.

Front 31

Phase Diagram

Back 31

Diagrams showing phases present under equilibrium conditions and the phase compositions at each combination of temperature and overall composition.

Front 32

Solubility

Back 32

The amount of one material that will completely dissolve in a second material without creating a second phase

Front 33

Tie Line

Back 33

A horizontal line drawn in a two-phase region of a phase diagram to assist in determining the compositions of the two phases.

Front 34

Unlimited Solubility

Back 34

When the amount of one material that will dissolve in a second material without creating a second phase is unlimited

Front 35

Age hardening

Back 35

A strengthening mechanism that relies on a sequence of solid-state phase transformations in generating a dispersion of ultrafine particles of a second phase. A form of dispersion strengthening

Front 36

Eutectic

Back 36

A three-phase invariant reaction in which one liquid phase solidifies to produce two solid phases

Front 37

Eutectoid

Back 37

A three-phase invariant reaction in which one solid phase transforms to two different solid phases

Front 38

Hypereutectic

Back 38

Composition is more than the composition at which a three-phase reaction occurs

Front 39

Hypoeutectic

Back 39

Composition is less than the composition at which a three-phase reaction occurs

Front 40

Intermetallic Compound

Back 40

A compound formed of two or more metals that has its own unique composition, structure, and properties

Front 41

Matrix

Back 41

The continuous solid phase in a complex microstructure.

Front 42

Miscibility Gap

Back 42

A region in a phase diagram in which two phases, with essentially the same structure, do not mix, or have no solubility in on another

Front 43

Monotectic

Back 43

A three-phase reaction in which one liquid transforms to a solid and a second liquid on cooling

Front 44

Nonstoichiometric Intermetallic

Back 44

A phase formed by the combination of two components into a compound having a structure and properties different from either compoment.

Front 45

Peritectic

Back 45

A three-phase reaction in which a solid and a liquid combine to produce a second solid on cooling

Front 46

Peritectoid

Back 46

A three-phase reaction in which two solids combine to form a third solid on cooling

Front 47

Precipitate

Back 47

A solid phase that forms from the original matrix phase when the solubility limit is exceeded.

Front 48

Primary Microconstituent

Back 48

The microconstituent that forms before the start of a three-phase reaction

Front 49

Solvus

Back 49

A solubility curve that separates a single-solid phase region from a two-solid phase region

Front 50

Stoichiometric Intermetallic

Back 50

A phase formed by the combination of two components into a compound having a structure and properties different from either component

Front 51

Artificial aging

Back 51

Reheating a solution-treated and quenched alloy to a temperature below the solvus in order to provide the theral energy required for a precipitate to form

Front 52

Austenite

Back 52

The name given to the FCC crystal structure of iron and iron-carbon alloys

Front 53

Bainite

Back 53

A two-phase microconstituent, containing ferrite and cementite, that forms in steels that are isothermally transformed at relatively low temperatures

Front 54

Coherent precipitate

Back 54

A precipitate whose crystal structure and atomic arrangement have a continuous relationship with the matrix from which the precipitate is formed. Provides excellent disruption of the atomic arrangement and excellent strengthening

Front 55

Guinier-Preston (GP) zones

Back 55

Tiny clusters of atoms that precipitate from the matrix in the early stages of the age-hardening process.

Front 56

Martensite

Back 56

A metastable phase formed in steel and other materials by a diffusionless, athermal transformation

Front 57

Natural aging

Back 57

When a coherent precipitate forms from a solution-treated and quenched agehardened alloy at room temperature, providing optimum strengthening

Front 58

Pearlite

Back 58

A two-phase lamellar microconstituent, containing ferrite and cementite, that forms in steels cooled in a normal fashion or isothermally transformed at relatively high temperatures

Front 59

Solution treatment

Back 59

The first step in the age hardening heat treatment. Alloy is heated above the solvus temperature to dissolve any second phase and to produce a homogeneous single-phase structure

Front 60

Supersaturated solid solution

Back 60

The solid solution formed when a material is rapidly cooled from a high-temperature single-phase region to a low-temperature two-phase region without the second phase precipitating.