1、Designation: E1142 11Standard TerminologyRelating to Thermophysical Properties1This standard is issued under the fixed designation E1142; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parent
2、heses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This is a compilation of terms and correspondingdefinitions commonly used in the study of thermophysicalproperties. Terms that are generally understood
3、 or definedadequately in other readily available sources are either notincluded or their sources identified.1.2 A definition is a single sentence with additional infor-mation included in a Discussion. It is reviewed every fiveyears, and the year of the last review or revision is appended.1.3 Definit
4、ions identical to those published by anotherstandards organization orASTM Committee are identified withthe abbreviation of the name of the organization or theidentifying document and ASTM Committee.1.4 Definitions of terms specific to a particular field (such asdynamic mechanical measurements) are i
5、dentified with anitalicized introductory phrase.2. Referenced Documents2.1 ASTM Standards:2D4092 Terminology for Plastics: Dynamic MechanicalPropertiesE7 Terminology Relating to Metallography3. Terminology3.1 Terms and Definitions:absolute pressurepessure measured relative to zero pressurecorrespond
6、ing to empty space.DISCUSSIONAbsolute pressure is atmospheric pressure plus gagepressure.admittance, Ythe reciprocal of impedance.alpha (a) loss peakin dynamic mechanical measurement,first peak in the damping curve below the melt, in order ofdecreasing temperature or increasing frequency (E7, E04)(1
7、988).angular frequency, vthe number of radians per secondtraversed by a rotating vector that represents any periodicallyvarying quantity.DISCUSSIONAngular frequency, v, is equal to two p times thefrequency, f.anti-thixotropyan increase of the apparent viscosity underconstant shear stress or shear ra
8、te followed by a gradualrecovery when the stress or shear rate is reduced to zero.arrhenius equationa mathematical relationship between thespecific reaction rate and the temperature given ask 5 AeE/RT(1)where:k is the reaction rate constant, A is the frequency factor, E is theenergy of activation, R
9、 is the gas constant, and T is the absolutetemperature (1990).barometerAn instrument for measuring atmospheric pres-sure.beta (b) loss peakin dynamic mechanical measurement,second discrete peak in damping curve below the melt, inorder of decreasing temperature or increasing frequency(D4092, D20) (19
10、88).boiling pressureat a specific temperature, the value of thevapor pressure of the liquid at which it is equal to theexternal pressure (1988).boiling temperatureat a specific pressure, the temperatureat which the vapor pressure of the liquid is equal to theexternal pressure (1988).capacitancethat
11、property of a system of conductors anddielectrics that permits the storage of electrical charge whena potential difference exists between the conductors.DISCUSSIONCapacitance is the ratio of a quantity of electric charge,Q, to a potential difference, V. A capacitance value is always positive.The uni
12、t of capacitance is the farad, F, which is equivalent to onecoulomb per volt.Celsiusdesignation of the degree on the International Prac-tical Temperature Scale; also used for the name of the scale,1This terminology is under the jurisdiction of ASTM Committee E37 onThermal Measurements and are the di
13、rect responsibility of Subcommittee E37.03 onNomenclature and Definitions.Current edition approved April 1, 2011. Published May 2011. Originallyapproved in 1988. Last previous edition approved in 2010 as E1142 10. DOI:10.1520/E1142-11.2For referenced ASTM standards, visit the ASTM website, www.astm.
14、org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.as “Celsius
15、 Temperature Scale.” Formerly (prior to 1948)called “Centigrade.” The Celsius temperature scale is relatedto the International Kelvin Temperature Scale by the equa-tion Tc=T 273.16K (1988).Centigradesee Celsius.coeffcient of expansion see coefficient of linear thermalexpansion.coefficient of linear
16、thermal expansion, alchange inlength, relative to the length of the specimen, accompanyinga unit change of temperature, at a specified temperature(1988).coefficient of viscositythe ratio between an infinitesimallysmall increase in stress and the corresponding increase instrain rate.coefficient of vo
17、lume thermal expansion avfor a solid orliquid, the change in volume, relative to the volume of thespecimen, accompanying a change of temperature at aspecified temperature (1988).color temperaturetemperature in degrees Kelvin (K) atwhich a black body must be operated to give a color equal tothat of t
18、he source in question (1988).complex modulus, E*, G*, or K*ratio of the stress to strainwhere each is a factor that may be represented by a complexnumber as follows: E*=E8 +iE9, G*=G8 +iG9, andK*=K8 +iK9.where:E* = complex modulus, measured in tension or flexure,E8 = storage modulus, measured in ten
19、sion or flexure,E9 = loss modulus, measured in tension or flexure,G* = complex modulus, measured in shear,G8 = storage modulus, measured in shear,G9 = loss modulus, measured in shear,K* = complex modulus, measured in compression,K8 = storage modulus, measured in compressionK9 = loss modulus, measure
20、d in compression, andi=1 , measured in compression.The complex modulus may be measured in tension orflexure, (E*), compression, (K*), or in shear, (G*)(D4092,D20) (1988).complex shear compliance, J*reciprocal of complex shearmodulus, where J* = 1/G* (D4092, D20) (1988).complex tensile compliance, D*
21、reciprocal of complex ten-sile modulus, where D*=1/E*(D4092, D20) (1988).complex viscosity, h*the complex modulus divided by theimposed frequency in rad/pliance, Jthe strain divided by the corresponding stress.DISCUSSIONCompliance is the reciprocal of positionquantity of the components of a mixture;
22、 usu-ally expressed in terms of the weight percentage, or theatomic percentage of each of the components in the mixture,(E7, E04) (1988).conductivity, electrical (volume), s the ratio of the currentdensity (Acm2) through a specimen to the potentialgradient ( V/cm) in the same direction as the curren
23、t.DISCUSSIONConductivity is normally expressed in units (ohmcm)1, but the correct SI units are Siemenm.congruent phasesthose states of matter of unique composi-tion that co-exist at equilibrium at a single point in tempera-ture and pressure; for example, the two coexisting phases ofa two-phase equil
24、ibrium (E7, E04) (1988).congruent transformationan isothermal, or isobaric, phasechange in which both of the phases concerned have the samecomposition throughout the process; the order of a systembecomes unary at a composition of congruency (E7, E04)(1988).constitutional diagramgraphical representat
25、ion of the com-positions, temperatures, pressures, or combinations thereofat which the heterogeneous equilibria of a system occur(1988).cooling curvegraphical representation of specimen tempera-ture or temperature change as a function of time or decreas-ing environment temperature (1988).cooling rat
26、eaverage slope of the time-temperature curvetaken over a specific time and temperature interval as thetemperature is decreased (1988).critical curvein a binary, or higher order, phase diagram, alocus of points along which two or more phases exist instable thermodynamic equilibrium.critical pointin a
27、 binary phase diagram, that specific valueof composition, temperature, pressure, or combinationsthereof at which the phases of a heterogeneous equilibriumbecome identical (1989).critical pressurethat pressure at the critical point (1990).critical surfacein a ternary or higher order phase diagram,the
28、 area upon which the phases in equilibrium becomeidentical (E7, E04) (1988).critical temperaturethat temperature at the critical point(1990).crystalsolid composed of atoms, ions, or molecules, ar-ranged in a pattern which is periodic in three dimensions(E7, E04) (1988).crystallinityregular arrangeme
29、nt of the atoms of a solid inspace (1988).DISCUSSIONIn most materials, this state is usually imperfectlyachieved. The crystalline regions (ordered regions) are submicroscopicvolumes in which there is more or less regularity of arrangement of thecomponent molecules.crystallitecrystalline grain not bo
30、unded by habit planes (E7,E04) (1988).crystallizationarrangement of previously disordered mate-rial segments of repeating patterns into geometric symmetry(1988).crystallization temperaturethat temperature at which aspecimen undergoes crystallization upon cooling (1988).Curie pointsee Curie temperatu
31、re.Curie temperaturetemperature above which a ferromag-netic or ferroelectric material becomes paramagnetic, orparaelectric, respectively (1997).DISCUSSIONThere may be more than one if there are multiplematerials.dampingloss in energy, dissipated as heat, that results whena material or material syst
32、em is subjected to an oscillatoryload or displacement (D4092, D20) (1988).devitrificationcrystallization of an amorphous substance(E7, E04) (1988).E1142 112dielectric constantsee permittivity, relative.dielectric dissipation factor, Dthe ratio of the loss factor,9, to the absolute permittivity, 8,or
33、D 59/8 (2)DISCUSSIONThe dielectric dissipation factor is numerically equal tothe tangent of the dielectric loss angle and may be referred to as the losstangent, tan d, or the cotangent of the phase angle, u.dielectric loss anglethe angle whose tangent is the dissipa-tion factor or arctan 9/8.DISCUSS
34、IONIt is also the difference between 90 degrees and thephase angle.differential thermocouplesee differential thermopile.differential thermopilea number of temperature sensorsconnected in series-opposing and arranged so that there is anincrease in output signal for a given temperature differencebetwe
35、en alternate junctions maintained at a reference tem-perature and the measured temperature (1989).dilatancythe increase in volume caused by shear.dipole relaxation time, gthe exponential decay time re-quired for the electric polarization of any point of a suitablycharged dielectric to fall from its
36、original value to 1/e of thatvalue, due to the loss of dipole orientation.DISCUSSIONUnder conditions of an alternating applied field and insystems with a single dipole relaxation time, it is equal to 1/v at the lossfactor peak in cases where the peak is caused by a dipole mechanism.dissipation facto
37、rsee tangent delta.dissociationas applied to heterogeneous equilibria, thetransformation of one phase into two or more new phases, allof different composition (E7, E04) (1988).dynamic modulussee complex modulus.elasticitythat property of materials that causes them to returnto their original form or
38、condition after the applied force isremoved (D4092, D20) (1988).elastic modulussee complex modulus and storage modu-lus.enthalpya thermodynamic function defined by the equationH= U + PV where H is the enthalpy, U is the internalenergy, P is the pressure, and V the volume of the system.DISCUSSIONAt c
39、onstant pressure the change in enthalpy measuresthe quantity of heat exchanged by the system and its surrounding.equilibrium diagram see constitutional diagram.eutectic pointsee eutectic.eutecticmixture of two or more substances which solidifiesas a whole when cooled from the liquid state, without c
40、hangein composition (1988).DISCUSSIONThe temperature at which the eutectic mixture solidifiesis called the eutectic point. This temperature is constant for a givencomposition, and represents the lowest melting point of the system.failurean arbitrary point beyond which a material ceases tobe function
41、ally capable of its intended use.failure temperature (Tf)the temperature at which a materialfails.Fahrenheitdesignation of a degree on the Fahrenheit tem-perature scale that is related to the International PracticalTemperature Scale by means of the equation: TF= 1.8TC+ 32.where:TFis the temperature
42、in degree Fahrenheit and TCis thetemperature in degrees Celsius (1988).freezing temperaturesee crystallization temperature.frequency, fthe number of cycles per unit time of periodicprocess.DISCUSSIONThe unit is Hertz (Hz) which is equal to 1 cycle per/s.frequency profilein dynamic mechanical measure
43、ment, plotof the dynamic properties of a material, at a constanttemperature, as a function of test frequency (D4092, D20)(1988).gage pressurepressure measured relative to atmosphericpressure.DISCUSSIONGage pressure is the difference between absolute pres-sure and atmospheric pressure.gamma (g) loss
44、peakin dynamic mechanical measurement,third peak in the damping curve below the melt, in the orderof decreasing temperature or increasing frequency (D4092,D20) (1988).Gibbs Phase Rulemaximum number of phases (P) that maycoexist at equilibrium is equal to two, plus the number ofcomponents (C) in the
45、mixture, minus the number of degreesof freedom (F): P+F=C+2(E7, E04) (1988).glass transitionreversible change in an amorphous materialor in amorphous regions of a partially crystalline material,from (or to) a viscous or rubbery condition to (or from) ahard and relatively brittle one (1988).DISCUSSIO
46、NThe glass transition generally occurs over a relativelynarrow temperature region and is similar to the solidification of a liquidto a glassy state. Not only do hardness and brittleness undergo rapidchanges in this temperature region, but other properties, such ascoefficient of thermal expansion and
47、 specific heat capacity, also changerapidly. This phenomenon sometimes is referred to as a second ordertransition, rubber transition, or rubbery transition. When more than oneamorphous transition occurs in a material, the one associated withsegmental motions of the backbone molecular chain, or accom
48、paniedby the largest change in properties is usually considered to be the glasstransition.glass transition temperaturea temperature chosen to rep-resent the temperature range over which the glass transitiontakes place (1989).DISCUSSIONThe glass transition temperature can be determinedreadily by obse
49、rving the temperature region at which a significantchange takes place in some specific electrical, mechanical, thermal, orother physical property. Moreover, the observed temperature can varysignificantly depending on the property chosen for observation and ondetails of the experimental technique (for example, heating rate,frequency of test). Therefore, the observed Tg should be consideredvalid only for that particular technique and set of test conditions.heat capaci
