Designation:E 7–03
Standard Terminology Relating to
Metallography 1
This standard is issued under the fixed designation E 7;the number immediately following the designation indicates the year of original adoption or,in the ca of revision,the year of last revision.A number in parenthes indicates the year of last reapproval.A superscript epsilon (e )indicates an editorial change since the last revision or reapproval.This standard has been approved for u by agencies of the Department of Defen.
1.Scope
1.1This standard covers the definition of terms,acronyms,and symbols ud in ASTM documents related to the field of metallography and metallographic testing.Terms that are only relevant to a particular standard or that are adequately defined in a general dictionary are not defined in this terminology standard.死亡魔法
1.2This standard includes terminology ud in metallo-graphic areas,such as,but not limited to:light microscopy,microindentation hardness testing,specimen preparation,x-ray and electron metallography,quantitative metallography,pho-tomicrography,and determination of grain size and inclusion content.
1.3This standard may be of u to individuals utilizing standards of Committee E-4as well as by tho in need of a general reference source for terminology in the field of metallography.
2.Referenced Documents 2.1ASTM Standards:
E 14Practice for Thermal Analysis of Metals and Alloys 2E 45Test Methods for Determining the Inclusion Content of Steel 3
E 80Practice for Dilatometric Analysis of Metallic Materi-als 4
E 92Test Method for Vickers Hardness of Metallic Mate-rials 3
E 112Test Methods for Determining Average Grain Size 3E 1122Practice for Obtaining JK Inclusion Ratings Using Automatic Image Analysis 33.Significance and U
3.1Standards of Committee E-4consist of test methods,practices,and guides developed to ensure proper and uniform
testing in the field of metallography.In order for one to properly u and interpret the standards,the terminology ud in the standards must be understood.
3.2The terms ud in the field of metallography have preci definitions.The terminology and its proper usage must be completely understood in order to adequately communicate in this field.In this respect,this standard is also a general source of terminology relating to the field of metallography facilitating the transfer of information within the field.
4.Terminology
absorption —the decrea in intensity which radiation under-goes during its passage through matter when the ratio of transmitted or reflected luminous flux to incident is less than 1.
absorption coefficient —specific factor characteristic of a substance on which its absorption radiation depends.The rate of decrea of the natural logarithm of the intensity of a parallel beam per unit distance traverd in a substance.For X-rays,the linear absorption coefficient is the natural loga-rithm of the ratio of the incident intensity of an X-ray beam incident on unit thickness of an absorbing material to the intensity of the beam transmitted.If I e is the incident inten-sity of a beam of X-rays,I t the transmitted intensity,and X the thickness of the absorbing material,then:
I t 5I e exp ~2µX !
(1)
Here µis the linear absorption coefficient.The mass absorption coefficient is given by µ/r where r is the density.
absorption edge —an abrupt change in absorption coefficient at a particular wavelength.The absorption coefficient is always larger on the short wavelength side of the absorption edge.
absorption limit —See absorption edge.
accelerating potential —a relatively high voltage applied be-tween the cathode and anode of an elect
ron gun to accelerate electrons.
achromatic —literally,color-free.A lens or prism is said to be achromatic when corrected for two colors.The remaining color en in an image formed by such a lens is said to be condary chromatic aberration.See apochromatic objec-tive
1
This terminology is under the jurisdiction of ASTM Committee E04on Metallography and are the direct responsibility of Subcommittee E04.02on Metallographic Terminology and Nomenclature of Pha Diagrams.
Current edition approved May 10,2003.Published June 2003.Originally approved in 1926.Last previous edition approved 2001as E 7–01.2
Annual Book of ASTM Standards ,V ol 04.01.3
Annual Book of ASTM Standards,V ol 03.01.4
Discontinued;e 1984Annual Book of ASTM Standards ,V ol 14.02.Replaced by E228.
1
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achromatic objective—an objective that is corrected chro-matically for two colors,and spherically for one,usually in the yellow-green part of the spectrum.
achromatic objective lens—an objective lens with longitudi-nal chromatic correction for green and blu
e,and spherical chromatic correction for green.Note—Lens should be ud with a greenfilter.
acid extraction—See extraction.
air-lock—an intermediate enclod chamber of a vacuum or pressure system through which an object may be pasd without materially changing the vacuum or pressure of the system.
alignment—a mechanical or electrical adjustment of the components of an optical device in such a way that the path of the radiating beam coincides with the optical axis or other predetermined path in the system.In electron optics there are three general types:
(1)magnetic alignment—an alignment of the electron optical axis of the electron microscope such that the image rotates about a point in the center of the viewing screen when the currentflowing through a lens is varied.
(2)mechanical alignment—a method of aligning the geometrical axis of the electron microscope by relative physical movement of the components,usually as a step preceding either magnetic or voltage alignment.
(3)voltage alignment—a condition of alignment of an electron microscope such that the image expan
ds or con-tracts symmetrically about the center of the viewing screen when the accelerating voltage is changed. allotriomorphic crystal—a crystal who lattice structure is normal,but who outward shape is imperfect since it is determined to some extent by the surroundings;the grains in a metallic aggregate are allotriomorphic crystals.
alloy system—a complete ries of compositions produced by mixing in all proportions any group of two,or more, components,at least one of which is a metal.
alpha brass—a solid solution pha of one or more alloying elements in copper and having the same crystal lattice as copper.
alpha iron(Fe)—solid pha of pure iron which is stable at temperatures below910°C and posss the body-centered cubic lattice.It is ferro-magnetic below768°C.
amplifier—a negative lens,ud in lieu of an eyepiece,to project under magnification the image formed by an objec-tive.The amplifier is especially designed forflatness offield and should be ud with an apochromatic objective. ampliphan eyepiece—See amplifier.
analyzer—an optical device,capable of producing plane polarized light,ud for detecting the state of
polarization. angle of reflection:(1)reflection—the angle between the reflected beam and the normal to the reflecting surface. (2)diffraction—the angle between the diffracted beam and the diffracting planes.
Angstrom unit(abbreviation)=A,Å,or A.U—a unit of length equal to10−8cm.This is the standard unit of measurement in X-ray crystallography.
angular aperture—See aperture,optical.anisotropic(replaces anisotropy)—having different values for a property,in different directions.
annealing-twin bands—See twin bands.
anode aperture—See aperture.
anvil—the ba on which objects for hardness test are placed. anvil effect—the effect caud by u of too high a load or when testing the hardness of too thin a specimen,resulting in a bulge or shiny spot on the under side of the specimen. aperture,electron:
anode aperture—the opening in the accelerating voltage anode shield of the electron gun through which the electrons must pass to illuminate or irradiate the specimen. condenr aperture—an openi
ng in the condenr lens controlling the number of electrons entering the lens and the angular aperture of the illuminating beam.The angular aperture can also be controlled by the condenr lens current. physical objective aperture—a metal diaphragm,centrally pierced with a small hole,ud to limit the cone of electrons accepted by the objective lens.This improves image contrast since highly scattered electrons are prevented from arriving at the Gaussian image plane and therefore can not contribute to background fog.
aperture,optical—the working diameter of a lens or a mirror. angular aperture—the angle between the most divergent rays which can pass through a lens to form the image of an object.
aperture diaphragm—a device to define the aperture. apochromatic objective—an objective with longitudinal chro-matic correction for red,green and blue,and spherical chromatic correction for green and blue.This is the best choice for high resolution or color photomicrography. arcing—in electron diffraction,the production of gments of circular patterns,indicating a departure from completely random orientation of the crystals of the specimen. arrest—that portion of a cooling curve in which temperature is invariant with time(for example,thermal or eutectic arrest). artifact—a fal microstructural feature that is not an actual characteristic of the specimen;it may be prent as a result of improper or inadequate preparation,handling methods,or optical conditions for viewing.
ascending fork point—in a ternary pha diagram,the con-figuration at the convergence of the three bivariant curves upon each of the four phas associated in Class II univariant equilibrium;for example,the union of two ascending liqui-dus surface valleys to form one ascending liquidus surface valley.
aspect ratio—the length-to-width ratio of a microstructural feature in a two-dimensional plane.
asterism—a lengthening of diffraction spots usually in the radial direction.
astigmatism—a defect in a lens or optical system which caus rays in one plane parallel to the optical axis to focus at a distance different from tho in the plane at right angles to it.
ASTM grain size number—See grain size. athermal—not isothermal,with changing rather than constant temperature
conditions.
atomic replica—See replica.
atomic scattering factor—the ratio of the amplitude of the wave scattered by an atom to that scattered by a single electron.Symbol=f.
austenite—a face-centered cubic solid solution of carbon or other elements in gamma iron.clau
austenite grain size—the grain size which exists or existed in austenite at a given temperature.See Test Methods E112. autographic dilatometer—a dilatometer that automatically records instantaneous and continuous changes in dimensions and some other controlled variable such as temperature or time.
autographic pyrometer—See pyrometer.
automatic image analysis—the paration and quantitative evaluation of an image into its elements with or without operator interaction.It includes the enhancement,detection, and quantification of the features contained in an image through the u of optical,geometrical,and stereological parameters and a computer program.Image analysis data output can provide individual measurements on each pa-rate feature(feature specific)or totals for all features of a particular type in thefield(field specific).
automatic image analyzer—a device which can be pro-grammed to detect and measure features of interest in an image.It may include accessories such as automatic focus and an automatic traversing stage to permit unattended operation.
average coefficient of cubical expansion—average change in unit volume of a substance per unit change in temperature over a specified range of temperature.
average coefficient of linear expansion—average change in unit length of a body per unit change in temperature over a specified range of temperature.
average coefficient of thermal expansion—general term. (See also average coefficient of cubical expansion and average coefficient of linear expansion.)
average grain diameter—See grain size.
axial ratio—the ratio of the length of one axis to that of another(for example,c/a)or the continued ratio of three axes(for example,a:b:c).
axis(crystal)—the edge of the unit cell of a space lattice.Any one axis of any one lattice is defined,in length and direction, with respect to the other axes of that lattice.
Babo’s law—the vapor pressure over a liquid solvent is lowered approximately in proportion to the quantity of a nonvolatile solute dissolved in the liquid.
backingfilm—afilm ud as auxiliary support for the thin replica or specimen-supportingfilm.
back reflection—the diffraction of X-rays at a Bragg angle approaching90°.
绯闻女孩 第四季background blackening—a continuous,slowly varying blackening of photographicfilm which has been expod to diffracted X-rays,on which the blackening due to diffracted spots or lines is superimpod.
bainite—upper,lower,intermediate—metastable micro-structure or microstructures resulting from the transforma-tion of austenite at temperatures between tho which produce pearlite and martensite.The structures may be
formed on continuous(slow)cooling if the transformation rate of austenite to pearlite is much slower than that of austenite to bainite.Ordinarily,the structures may be formed isothermally at temperatures within the above range by quenching austenite to a desired temperature and holding for a period of time necessary for transformation to occur.If the transformation temperature is just bel
ow that at which thefinest pearlite is formed,the bainite(upper bainite)has a feathery appearance.If the transformation temperature is just above that at which martensite is produced,the bainite (lower bainite)is acicular,rembling slightly tempered martensite.At the higher resolution of the electron micro-scope,upper bainite is obrved to consist of plates of cementite in a matrix of ferrite.The discontinuous carbide plates tend to have parallel orientation in the direction of the longer dimension of the bainite areas.Lower bainite consists of ferrite needles containing carbide platelets in parallel array cross-striating each needle axis at an angle of about 60°.Intermediate bainite rembles upper bainite;however, the carbides are smaller and more randomly oriented. balancedfilters(X-rays)—a pair offilters ud to eliminate all but a narrow range of wavelengths.Thefilter materials and thickness are chon so that their absorption edges lie very clo together and so that they have the same absorption except for wavelengths lying in the range between their absorption edges.When thefilters are ud alternately,the difference in effect,if any,is due to X-rays that have wavelengths in this range.Balancedfilters thus can be made to rve as a crude monochromator.
band—in electron diffraction,a broad intensity maximum with sharp edges.
banded structure(banding)—alternate bands parallel with the direction of working resulting from the elongation of gregated areas.
barrel distortion—See distortion.
basal plane—that plane of a hexagonal or tetragonal crystal which is perpendicular to the axis of highest symmetry.Its Miller indices are(0001)or(001),respectively.
bellows length—the distance from the eyepiece to the photo-nsitive material or viewing screen in a photomicrographic apparatus.
Bertrand lens—an auxiliary removable lens in the body of a microscope,ud to examine images in the back focal plane of the objective,for example,interferencefigures with polarized light.
beta structure—structurally analogous body-centered cubic phas(similar to beta brass),or electron compounds,that have ratios of3valence electrons to2atoms.
biad gun—an electron gun in which there is a bias voltage on the cathode cap.(See also lf-biad gun.)
bifilar eyepiece—a Filar eyepiece with motion in two mutually perpendicular directions.
binary alloy—any specific composition in a binary system. binary system—the complete ries of co
mpositions produced by mixing a pair of components in all proportions. binodal curve—in a two-dimensional pha diagram,a con-tinuous line consisting of both of the pair of conjugate boundaries of a two-pha equilibrium and which
make the days count
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without inflection,at a critical point.See miscibility gap. birefringent—having more than one refractive index.Such materials exhibit alternately bright and dark reflections at 45°intervals during a360°rotation with plane-polarized light.(See also anisotropic.)
bivariant equilibrium—a stable state among a number of phas equal to the number of components in a system and in which any two of the external variables(temperature, pressure,or concentrations)may be varied,at will,without necessarily causing a change in the number of phas; sometimes called divariant equilibrium.
blowholes—a hole produced in a casting by gas which was trapped during solidification.
body-centered—having an atom(or group of atoms)parated by a translation of1⁄2,1⁄2,1⁄2from a similar atom(or group of atoms).The number of atoms in a body-centered cell must be a multiple of two.
boiling pressure—at a specified temperature,the pressure at which a liquid and its vapor are in equilibrium.
boiling temperature—at a specified pressure,the temperature at which a liquid and its vapor are in equilibrium. bonded abrasive disk—a rigid support surface with an abra-sive,typically diamond,bonded to the surface by a ceramic, resin,or metal bad material.
boundary grain—in the Jeffries’method for grain size mea-surement,a grain that is intercted by the boundary of the standard area and is,therefore,counted only as one-half grain.(See also Jeffries’Method.)
Bragg angle—the angle between the incident beam and the lattice planes considered.
Bragg equation:—
n l52d sin u(2) where:
n=order of reflection,
l=wavelength of X-rays,
d=distance between lattice planes,and
u=Bragg angle.
Bragg method—a method of X-ray diffraction in which a single crystal is mounted on a spectrometer with a crystal face parallel to the axis of the instrument.
Braun’s law—the ratio of the solubility change with pressure, temperature being constant,(d X/d P)T,to the solubility change with temperature,pressure being constant,(d X/d T)P,is equal to the negative of the product of the absolute temperature,T,and the(fictitious)volume change (D v)which accompanies the solution of1g·molecular weight of the solute in an infinitely large quantity of the saturated solution at T degrees,divided by the amount of heat,Q,developed in the process:
~d X/d P!T/~d X d T!P52T·D v/Q(3) brightfield illumination—for reflected light,the illumination which caus specularly reflected surfaces normal to the axis of a microscope to appear bright.For transmission electron microscopy,the illumination of an object so that it appears on a bright backgrou
nd.
soldeburning(burnt,burned)—a term applied to metal which has been permanently damaged by having been heated to a
temperature clo to or within the melting range.This results in a structure exhibiting incipient melting or intergranular oxidation.
calibration—1)the act or process of determining the relation-ship between a t of standard units of measure and the output of an instrument or test procedure,
2)the graphical or mathematical relationship relating the desired property(expresd in a standard unit of measure such as micrometers or Kg/mm2)to the instrument output (instrument units such asfilar divisions or pixels).
caliper diameter(Feret’s diameter)—the length of a line normal to two parallel lines,tangent to opposite edges of a pha or object.
carbide—a compound of carbon with one or more elements, which,in customary formulation,are considered as being more positive than carbon.
ca—in a ferrous alloy,the outer portion that has been made harder than the inner portion(e core)as a result of altered composition,or structure,or both,from treatments such as carburizing,nitriding,and induction hardening. castte—a light-tightfilm or plate holder.
cast replica—See replica.
cast structure—the structure,on a macroscopic or micro-scopic scale,of a casting.
cathode lens—a lensfield terminated on one side by a surface at zero potential(cathode)normal to the optic axis.A cathode lens occurs in any system in which a cathode is imaged by its own electron emission,be it thermionic, photoelectric,condary,orfield emission. cementite—a very hard and brittle compound of iron and carbon corresponding to the empirical formula Fe3C.It is commonly known as iron carbide and posss an orthor-hombic lattice.In“plain-carbon steels”some of the iron atoms in the cementite lattice are replaced by mangane, and in“alloy steels”by other elements such as chromium or tungsten.Cementite will often appear as distinct lamellae or as spheroids or globules of varying size in hypo-eutectoid steels.Cementite is in metastable equilibrium and has a tendency to decompo into iron and graphite,although the reaction rate is very slow.
central pencil—a bundle of rays originating in the axis with an angular aperture equal to the effective
aperture of the lens. The rays pass through the lens aperture and contribute to the formation of the image.
certified reference material—a reference material,the com-position or properties of which are certified by a recognized standardizing agency or group.Typically such a material is accompanied by documentation(certificate). characteristic curve—the curve showing the relationship between exposure and resulting density in a photographic image.It is usually plotted as the density against the log exposure.Called also the“H and D curve”and the“nsi-tometric curve.”
characteristic radiation—X-radiation of a particular t of wavelengths,produced by and characteristic of a particular element ud as a target whenever its excitation potential is
exceeded.
charge neutralizer gun—an electron gun ud to dissipate the charges which tend to build up on spe
cimen surfaces,within an electron-diffraction camera,which would introduce un-desired electrostaticfields.
chemical potential—(µi or G¯i)the partial molar free energy of component i,that is,the change in free energy of a solution upon adding one mole of component i to an infinite amount of solution of given composition,
~d G/d n i!T,P,n
1···
5G¯i5µi(4) where:
G=Gibbs free energy,and
n i=number of moles of the i th component.
Chine script eutectic—a configuration of eutectic constitu-ents,found particularly in some cast alloys of aluminum containing iron and silicon and in magnesium alloys con-taining silicon,which rembles in appearance the characters in Chine script.
chlorine or volatile halide extraction—See extraction. chromatic aberration—a defect in a lens or lens system as a result of which the lens posss different focal lengths for radiation of different wavelengths.
Class I quaternary equilibrium—in a four-component sys-tem,the stable univariant coexistence offive phas,one of which must disappear upon lowering the temperature or pressure;for example,the quaternary eutectic equilibrium, L=a+b+g+d.
Class I quinary equilibrium—in afive-component system, the stable univariant coexistence of six phas,one of which must disappear upon lowering the temperature or pressure; for example,the quinary eutectic equilibrium, L=a+b+g+s+e.
Class I ternary equilibrium—in a three-component system, the stable univariant coexistence of four phas,one of which must disappear upon lowering the temperature or pressure;for example,the ternary eutectic equilibrium, L=a+b+d.
Class II quaternary equilibrium—in a four-component sys-tem,the stable univariant coexistence offive phas,two of which appear in each of the three associated bivariant equilibria at temperatures and pressures above,while the other three phas all occur in both of the associated bi
variant equilibria below;for example,L+a=b+g+d. Class II quinary equilibrium—in afive-component system, the stable univariant coexistence of six phas,two of which appear in each of the four associated bivariant equilibria at temperatures and pressures above,while the other four phas occur in both of the associated bivariant equilibria below;for example,L+a=b+g+d+e.
Class II ternary equilibrium—in a three-component system, the stable univariant coexistence of four phas,two of which appear in both of the associated bivariant equilibria at higher temperature and pressure,while the other two phas occur in both bivariant equilibria below;for example, L+a=b+g.
Class III quaternary equilibrium—in a four-component system,the stable univariant coexistence offive phas, three of which appear in both of the associated bivariant
equilibria at temperatures and pressures above,while the other two phas occur in all three of the associated bivariant equilibria below;for example,L+a+b=g+d.
Class III quinary equilibrium—in afive-component system, the stable univariant coexistence of six phas,three of which appear in all three of the associated bivariant equilib-ria at temperatures and pressures above,while the other three occur in all three of the associated bivariant equilibria below; for example,L+a+b=g+d+e.
Class III ternary equilibrium—in a three-component system, the stable univariant coexistence of four phas,one of which must disappear at higher temperature or pressure;for example,the ternary peritectic equilibrium,L+a+b=g. Class IV quaternary equilibrium—in a four-component system,the stable univariant coexistence offive phas,one of which must disappear at higher temperature or pressure; for example,the quaternary peritectic equilibrium, L+a+b+g=d.
Class IV quinary equilibrium—in afive-component system, the stable univariant coexistence of six phas,four of which appear in both associated bivariant equilibria at temperatures and pressures above,while the other two occur in all four associated bivariant equilibria below;for example, L+a+b+g=d+e.
Class V quinary equilibrium—in afive-component system, the stable univariant coexistence of six phas,one of which must disappear upon increasing the temperature or pressure; for example,the quinary peritectic equilibrium, L+a+b+g+d=e.
Clausius-Clapeyron equation—the rate of change of the pressure of a heterogeneous equilibrium with change of temperature d P/d T is equal to the heat of transformation from the low to the high temperature state D Hv divided by the product of the absolute temperature of the equilibrium and the volume change of the transformation T D V:
d P/dT5D Hv/T D V(5)
or,
d ln P/d T'Hv/RT(6) wher
e R is the gas constant and the equilibrium is not near a critical point.杭州新东方英语
clear cross test—an experimental method for determining which of two conceivable two-pha equilibria is real;at that composition at which the two conceivable two-phafields cross,an alloy is brought to equilibrium and the phas identified;the same principle may be applied to higher-order equilibria in higher-order systems.drive by
clear glass focusing screen—a glass screen polished on both sides and mounted for u in a camera,in lieu of photo-nsitive material,for the purpo of establishing a plane on which to focus an image prior to recording it.
cleavage planes—that family of planes of a crystal along which the crystal is easily split.
clo packed—a geometric arrangement whereby a collection of equally sized spheres(atoms)may be packed together in a minimum total volume.
coefficient of thermal expansion—change in unit of length(or volume)accompanying a unit change of temperature,at
a
