1、Designation:E703Standard Terminology Relating toMetallography1This standard is issued under the fixed designation E 7; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision. A number in parentheses indicates the
2、 year of last reapproval. A superscriptepsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This standard covers the definition of terms, acronyms,and symbols used in ASTM document
3、s related to the field ofmetallography and metallographic testing. Terms that are onlyrelevant to a particular standard or that are adequately definedin a general dictionary are not defined in this terminologystandard.1.2 This standard includes terminology used in metallo-graphic areas, such as, but
4、 not limited to: light microscopy,microindentation hardness testing, specimen preparation, x-rayand electron metallography, quantitative metallography, pho-tomicrography, and determination of grain size and inclusioncontent.1.3 This standard may be of use to individuals utilizingstandards of Committ
5、ee E-4 as well as by those in need of ageneral reference source for terminology in the field ofmetallography.2. Referenced Documents2.1 ASTM Standards:E 14 Practice for Thermal Analysis of Metals and Alloys2E 45 Test Methods for Determining the Inclusion Contentof Steel3E 80 Practice for Dilatometri
6、c Analysis of Metallic Materi-als4E 92 Test Method for Vickers Hardness of Metallic Mate-rials3E 112 Test Methods for Determining Average Grain Size3E 1122 Practice for Obtaining JK Inclusion Ratings UsingAutomatic Image Analysis33. Significance and Use3.1 Standards of Committee E-4 consist of test
7、methods,practices, and guides developed to ensure proper and uniformtesting in the field of metallography. In order for one toproperly use and interpret these standards, the terminologyused in these standards must be understood.3.2 The terms used in the field of metallography haveprecise definitions
8、. The terminology and its proper usage mustbe completely understood in order to adequately communicatein this field. In this respect, this standard is also a generalsource of terminology relating to the field of metallographyfacilitating the transfer of information within the field.4. Terminologyabs
9、orptionthe decrease in intensity which radiation under-goes during its passage through matter when the ratio oftransmitted or reflected luminous flux to incident is less than1.absorption coefficientspecific factor characteristic of asubstance on which its absorption radiation depends. Therate of dec
10、rease of the natural logarithm of the intensity of aparallel beam per unit distance traversed in a substance. ForX-rays, the linear absorption coefficient is the natural loga-rithm of the ratio of the incident intensity of an X-ray beamincident on unit thickness of an absorbing material to theintens
11、ity of the beam transmitted. If Ieis the incident inten-sity of a beam of X-rays, Itthe transmitted intensity, and Xthe thickness of the absorbing material, then:It5 Ieexp2X! (1)Here is the linear absorption coefficient. The mass absorptioncoefficient is given by /r where r is the density.absorption
12、 edgean abrupt change in absorption coefficientat a particular wavelength. The absorption coefficient isalways larger on the short wavelength side of the absorptionedge.absorption limitSee absorption edge.accelerating potentiala relatively high voltage applied be-tween the cathode and anode of an el
13、ectron gun to accelerateelectrons.achromaticliterally, color-free. A lens or prism is said to beachromatic when corrected for two colors. The remainingcolor seen in an image formed by such a lens is said to besecondary chromatic aberration. See apochromatic objec-tive1This terminology is under the j
14、urisdiction of ASTM Committee E04 onMetallography and are the direct responsibility of Subcommittee E04.02 onMetallographic Terminology and Nomenclature of Phase Diagrams.Current edition approved May 10, 2003. Published June 2003. Originallyapproved in 1926. Last previous edition approved 2001 as E7
15、01.2Annual Book of ASTM Standards, Vol 04.01.3Annual Book of ASTM Standards, Vol 03.01.4Discontinued; see 1984 Annual Book of ASTM Standards, Vol 14.02. Replacedby E228.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.achromatic objec
16、tivean objective that is corrected chro-matically for two colors, and spherically for one, usually inthe yellow-green part of the spectrum.achromatic objective lensan objective lens with longitudi-nal chromatic correction for green and blue, and sphericalchromatic correction for green. NoteLens shou
17、ld be usedwith a green filter.acid extractionSee extraction.air-lockan intermediate enclosed chamber of a vacuum orpressure system through which an object may be passedwithout materially changing the vacuum or pressure of thesystem.alignmenta mechanical or electrical adjustment of thecomponents of a
18、n optical device in such a way that the pathof the radiating beam coincides with the optical axis or otherpredetermined path in the system. In electron optics there arethree general types:(1) magnetic alignmentan alignment of the electronoptical axis of the electron microscope such that the imagerot
19、ates about a point in the center of the viewing screen whenthe current flowing through a lens is varied.(2) mechanical alignmenta method of aligning thegeometrical axis of the electron microscope by relativephysical movement of the components, usually as a steppreceding either magnetic or voltage al
20、ignment.(3) voltage alignmenta condition of alignment of anelectron microscope such that the image expands or con-tracts symmetrically about the center of the viewing screenwhen the accelerating voltage is changed.allotriomorphic crystala crystal whose lattice structure isnormal, but whose outward s
21、hape is imperfect since it isdetermined to some extent by the surroundings; the grains ina metallic aggregate are allotriomorphic crystals.alloy systema complete series of compositions produced bymixing in all proportions any group of two, or more,components, at least one of which is a metal.alpha b
22、rassa solid solution phase of one or more alloyingelements in copper and having the same crystal lattice ascopper.alpha iron (Fe)solid phase of pure iron which is stable attemperatures below 910C and possesses the body-centeredcubic lattice. It is ferro-magnetic below 768C.amplifiera negative lens,
23、used in lieu of an eyepiece, toproject under magnification the image formed by an objec-tive. The amplifier is especially designed for flatness of fieldand should be used with an apochromatic objective.ampliphan eyepiece See amplifier.analyzeran optical device, capable of producing planepolarized li
24、ght, used for detecting the state of polarization.angle of reflection: ( 1) reflectionthe angle between thereflected beam and the normal to the reflecting surface.(2) diffractionthe angle between the diffracted beam andthe diffracting planes.Angstrom unit (abbreviation) = A, , or A. Ua unit oflength
25、 equal to 108cm. This is the standard unit ofmeasurement in X-ray crystallography.angular apertureSee aperture, optical.anisotropic (replaces anisotropy)having different values fora property, in different directions.annealing-twin bands See twin bands.anode apertureSee aperture.anvilthe base on whic
26、h objects for hardness test are placed.anvil effectthe effect caused by use of too high a load orwhen testing the hardness of too thin a specimen, resulting ina bulge or shiny spot on the under side of the specimen.aperture, electron:anode aperture the opening in the accelerating voltageanode shield
27、 of the electron gun through which the electronsmust pass to illuminate or irradiate the specimen.condenser aperturean opening in the condenser lenscontrolling the number of electrons entering the lens and theangular aperture of the illuminating beam. The angularaperture can also be controlled by th
28、e condenser lens current.physical objective aperturea metal diaphragm, centrallypierced with a small hole, used to limit the cone of electronsaccepted by the objective lens. This improves image contrastsince highly scattered electrons are prevented from arrivingat the Gaussian image plane and theref
29、ore can not contributeto background fog.aperture, opticalthe working diameter of a lens or a mirror.angular aperture the angle between the most divergentrays which can pass through a lens to form the image of anobject.aperture diaphragma device to define the aperture.apochromatic objectivean objecti
30、ve with longitudinal chro-matic correction for red, green and blue, and sphericalchromatic correction for green and blue. This is the bestchoice for high resolution or color photomicrography.arcingin electron diffraction, the production of segments ofcircular patterns, indicating a departure from co
31、mpletelyrandom orientation of the crystals of the specimen.arrestthat portion of a cooling curve in which temperature isinvariant with time (for example, thermal or eutectic arrest).artifacta false microstructural feature that is not an actualcharacteristic of the specimen; it may be present as a re
32、sultof improper or inadequate preparation, handling methods, oroptical conditions for viewing.ascending fork pointin a ternary phase diagram, the con-figuration at the convergence of the three bivariant curvesupon each of the four phases associated in Class II univariantequilibrium; for example, the
33、 union of two ascending liqui-dus surface valleys to form one ascending liquidus surfacevalley.aspect ratiothe length-to-width ratio of a microstructuralfeature in a two-dimensional plane.asterisma lengthening of diffraction spots usually in theradial direction.astigmatisma defect in a lens or optic
34、al system whichcauses rays in one plane parallel to the optical axis to focusat a distance different from those in the plane at right anglesto it.ASTM grain size number See grain size.athermalnot isothermal, with changing rather than constanttemperature conditions.E7032atomic replicaSee replica.atom
35、ic scattering factorthe ratio of the amplitude of thewave scattered by an atom to that scattered by a singleelectron. Symbol = f.austenitea face-centered cubic solid solution of carbon orother elements in gamma iron.austenite grain sizethe grain size which exists or existed inaustenite at a given te
36、mperature. See Test Methods E 112.autographic dilatometera dilatometer that automaticallyrecords instantaneous and continuous changes in dimensionsand some other controlled variable such as temperature ortime.autographic pyrometer See pyrometer.automatic image analysisthe separation and quantitative
37、evaluation of an image into its elements with or withoutoperator interaction. It includes the enhancement, detection,and quantification of the features contained in an imagethrough the use of optical, geometrical, and stereologicalparameters and a computer program. Image analysis dataoutput can prov
38、ide individual measurements on each sepa-rate feature (feature specific) or totals for all features of aparticular type in the field (field specific).automatic image analyzera device which can be pro-grammed to detect and measure features of interest in animage. It may include accessories such as au
39、tomatic focusand an automatic traversing stage to permit unattendedoperation.average coefficient of cubical expansion average change inunit volume of a substance per unit change in temperatureover a specified range of temperature.average coefficient of linear expansion average change inunit length o
40、f a body per unit change in temperature over aspecified range of temperature.average coefficient of thermal expansion general term.(See also average coefficient of cubical expansion andaverage coefficient of linear expansion.)average grain diameter See grain size.axial ratiothe ratio of the length o
41、f one axis to that ofanother (for example, c/a) or the continued ratio of threeaxes (for example, a:b:c).axis (crystal)the edge of the unit cell of a space lattice. Anyone axis of any one lattice is defined, in length and direction,with respect to the other axes of that lattice.Babos lawthe vapor pr
42、essure over a liquid solvent islowered approximately in proportion to the quantity of anonvolatile solute dissolved in the liquid.backing filma film used as auxiliary support for the thinreplica or specimen-supporting film.back reflectionthe diffraction of X-rays at a Bragg angleapproaching 90.backg
43、round blackeninga continuous, slowly varyingblackening of photographic film which has been exposed todiffracted X-rays, on which the blackening due to diffractedspots or lines is superimposed.bainiteupper, lower, intermediate metastable micro-structure or microstructures resulting from the transform
44、a-tion of austenite at temperatures between those whichproduce pearlite and martensite. These structures may beformed on continuous (slow) cooling if the transformationrate of austenite to pearlite is much slower than that ofaustenite to bainite. Ordinarily, these structures may beformed isothermall
45、y at temperatures within the above rangeby quenching austenite to a desired temperature and holdingfor a period of time necessary for transformation to occur. Ifthe transformation temperature is just below that at whichthe finest pearlite is formed, the bainite (upper bainite) has afeathery appearan
46、ce. If the transformation temperature is justabove that at which martensite is produced, the bainite(lower bainite) is acicular, resembling slightly temperedmartensite. At the higher resolution of the electron micro-scope, upper bainite is observed to consist of plates ofcementite in a matrix of fer
47、rite. These discontinuous carbideplates tend to have parallel orientation in the direction of thelonger dimension of the bainite areas. Lower bainite consistsof ferrite needles containing carbide platelets in parallelarray cross-striating each needle axis at an angle of about60. Intermediate bainite
48、 resembles upper bainite; however,the carbides are smaller and more randomly oriented.balanced filters (X-rays)a pair of filters used to eliminateall but a narrow range of wavelengths. The filter materialsand thicknesses are chosen so that their absorption edges lievery close together and so that th
49、ey have the same absorptionexcept for wavelengths lying in the range between theirabsorption edges. When these filters are used alternately, thedifference in effect, if any, is due to X-rays that havewavelengths in this range. Balanced filters thus can be madeto serve as a crude monochromator.bandin electron diffraction, a broad intensity maximum withsharp edges.banded structure (banding)alternate bands parallel withthe direction of working resulting from the elongation ofsegregated areas.barrel distortion
