1、Designation: E1142 11b E1142 12Standard 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
2、 in parentheses 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 corresponding definitions commonly used in the study of thermophysical properties.Terms that are generally
3、 understood or defined adequately in other readily available sources are either not included or their sourcesidentified.1.2 A definition is a single sentence with additional information included in a Discussion. It is reviewed every five years, andthe year of the last review or revision is appended.
4、1.3 Definitions identical to those published by another standards organization or ASTM Committee are identified with theabbreviation of the name of the organization or the identifying document and ASTM Committee.1.4 Definitions of terms specific to a particular field (such as dynamic mechanical meas
5、urements) are identified with anitalicized introductory phrase.2. Referenced Documents2.1 ASTM Standards:2D4092 Terminology for Plastics: Dynamic Mechanical PropertiesE7 Terminology Relating to MetallographyE344 Terminology Relating to Thermometry and Hydrometry3. Terminology3.1 Definitions:absolute
6、 pressure, npessure measured relative to zero pressure corresponding to empty space.DISCUSSIONAbsolute pressure is atmospheric pressure plus gage pressure.admittance, Y,nthe reciprocal of impedance.alpha () loss peak, nin dynamic mechanical measurement, first peak in the damping curve below the melt
7、, in order ofdecreasing temperature or increasing frequency. E7angular frequency, , nthe number of radians per second traversed by a rotating vector that represents any periodically varyingquantity.DISCUSSIONAngular frequency, , is equal to two pi times the frequency, f.anisotropic, adjhaving differ
8、ent values for a property in different directions.1 This terminology is under the jurisdiction of ASTM Committee E37 on Thermal Measurements and are the direct responsibility of Subcommittee E37.03 onNomenclature and Definitions.Current edition approved Aug. 1, 2011Sept. 1, 2012. Published August 20
9、11 October 2012. Originally approved in 1988. Last previous edition approved in 2011 asE1142 11a.E1142 11b. DOI: 10.1520/E1142-11B.10.1520/E1142-12.2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Stan
10、dardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible
11、 to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West C
12、onshohocken, PA 19428-2959. United States1anti-thixotropy, nan increase of the apparent viscosity under constant shear stress or shear rate followed by a gradual recoverywhen the stress or shear rate is reduced to zero.arrhenius equation, na mathematical relationship between the specific reaction ra
13、te and the temperature given as:k 5Ae2E/RT (1)where:k is the reaction rate constant, A is the frequency factor, E is the energy of activation, R is the gas constant, and T is the abso-lute temperature.barometer, nAn instrument for measuring atmospheric pressure.beta () loss peak, nin dynamic mechani
14、cal measurement, second discrete peak in damping curve below the melt, in order ofdecreasing temperature or increasing frequency. D4092boiling pressure, nat a specific temperature, the value of the vapor pressure of the liquid at which it is equal to the externalpressure.boiling temperature, nat a s
15、pecific pressure, the temperature at which the vapor pressure of the liquid is equal to the externalpressure.capacitance, nthat property of a system of conductors and dielectrics that permits the storage of electrical charge when apotential difference exists between the conductors.DISCUSSIONCapacita
16、nce is the ratio of a quantity of electric charge, Q, to a potential difference, V. A capacitance value is always positive. The unit of capacitanceis the farad, F, which is equivalent to one coulomb per volt.Celsius, ndesignation of the degree on the International Practical Temperature Scale; also u
17、sed for the name of the scale, as“Celsius Temperature Scale.” Formerly (prior to 1948) called “Centigrade.” The Celsius temperature scale is related to theInternational Kelvin Temperature Scale by the equation: Tc = T 273.16 K.Centigrade,nsee Celsius.coeffcient of expansion,nsee coefficient of linea
18、r thermal expansion.coefficient of linear thermal expansion, l,nchange in length, relative to the length of the specimen, accompanying a unitchange of temperature, at a specified temperature.coefficient of viscosity, nthe ratio between an infinitesimally small increase in stress and the correspondin
19、g increase in strainrate.coefficient of volume thermal expansion v,nfor a solid or liquid, the change in volume, relative to the volume of the specimen,accompanying a change of temperature at a specified temperature.color temperature, ntemperature in degrees Kelvin (K) at which a black body must be
20、operated to give a color equal to thatof the source in plex modulus, E*,G*, or K*,nratio of the stress to strain where each is a factor that may be represented by a complexnumber as follows: E* = E + iE“, G* = G + iG“, and K* = K + iK“.where:E* = complex modulus, measured in tension or flexure,E = s
21、torage modulus, measured in tension or flexure,E9 = loss modulus, measured in tension or flexure,G* = complex modulus, measured in shear,G = storage modulus, measured in shear,G9 = loss modulus, measured in shear,K* = complex modulus, measured in compression,K = storage modulus, measured in compress
22、ionK9 = loss modulus, measured in compression, andi521, measured in compression.The complex modulus may be measured in tension or flexure, (E*), compression, (K*), or in shear, (G*). D4092E1142 122complex shear compliance, J*,nreciprocal of complex shear modulus, where J* = 1/G*. D4092complex tensil
23、e compliance, D*,nreciprocal of complex tensile modulus, where D* = 1/E*. D4092complex viscosity, *, nthe complex modulus divided by the imposed frequency in rad/pliance, J,nthe strain divided by the corresponding stress.DISCUSSIONCompliance is the reciprocal of position, nquantity of the components
24、 of a mixture; usually expressed in terms of the weight percentage, or the atomicpercentage of each of the components in the mixture. E7conductivity, electrical (volume), , nthe ratio of the current density (Acm2) through a specimen to the potential gradient(V/cm) in the same direction as the curren
25、t.DISCUSSIONConductivity is normally expressed in units (ohmcm)1, but the correct SI units are Siemenm.congruent phases, nthose states of matter of unique composition that co-exist at equilibrium at a single point in temperatureand pressure; for example, the two coexisting phases of a two-phase equi
26、librium. E7congruent transformation, nan isothermal, or isobaric, phase change in which both of the phases concerned have the samecomposition throughout the process; the order of a system becomes unary at a composition of congruency. E7constitutional diagram, ngraphical representation of the composi
27、tions, temperatures, pressures, or combinations thereof atwhich the heterogeneous equilibria of a system occur.cooling curve, ngraphical representation of specimen temperature or temperature change as a function of time or decreasingenvironment temperature.cooling rate, naverage slope of the time-te
28、mperature curve taken over a specific time and temperature interval as the temperatureis decreased.critical curve, nin a binary, or higher order, phase diagram, a locus of points along which two or more phases exist in stablethermodynamic equilibrium.critical point, nin a binary phase diagram, that
29、specific value of composition, temperature, pressure, or combinations thereof atwhich the phases of a heterogeneous equilibrium become identical.critical pressure, nthat pressure at the critical point.critical surface, nin a ternary or higher order phase diagram, the area upon which the phases in eq
30、uilibrium become identical.E7critical temperature, nthat temperature at the critical point.crystal, nsolid composed of atoms, ions, or molecules, arranged in a pattern which is periodic in three dimensions. E7crystallinity, nregular arrangement of the atoms of a solid in space.DISCUSSIONIn most mate
31、rials, this state is usually imperfectly achieved. The crystalline regions (ordered regions) are submicroscopic volumes in which there ismore or less regularity of arrangement of the component molecules.crystallite, ncrystalline grain not bounded by habit planes. E7crystallization, narrangement of p
32、reviously disordered material segments of repeating patterns into geometric symmetry.crystallization temperature, nthat temperature at which a specimen undergoes crystallization upon cooling.Curie point,nsee Curie temperature.Curie temperature, ntemperature above which a ferromagnetic or ferroelectr
33、ic material becomes paramagnetic, or paraelectric,respectively.E1142 123DISCUSSIONThere may be more than one if there are multiple materials.damping, nloss in energy, dissipated as heat, that results when a material or material system is subjected to an oscillatory loador displacement. D4092devitrif
34、ication, ncrystallization of an amorphous substance. E7dielectric constant,nsee permittivity, relative.dielectric dissipation factor, D,nthe ratio of the loss factor, “, to the absolute permittivity, , or:D 5“/ (2)DISCUSSIONThe dielectric dissipation factor is numerically equal to the tangent of the
35、 dielectric loss angle and may be referred to as the loss tangent, tan , or thecotangent of the phase angle, .dielectric loss angle, nthe angle whose tangent is the dissipation factor or arctan “/.DISCUSSIONIt is also the difference between 90 degrees and the phase angle.differential thermocouple,ns
36、ee differential thermopile.differential thermopile, na number of temperature sensors connected in series-opposing and arranged so that there is an increasein output signal for a given temperature difference between alternate junctions maintained at a reference temperature and themeasured temperature
37、.dilatancy, nthe increase in volume caused by shear.dipole relaxation time, , nthe exponential decay time required for the electric polarization of any point of a suitably chargeddielectric to fall from its original value to 1/e of that value, due to the loss of dipole orientation.DISCUSSIONUnder co
38、nditions of an alternating applied field and in systems with a single dipole relaxation time, it is equal to 1/ at the loss factor peak in caseswhere the peak is caused by a dipole mechanism.dissipation factor,nsee tangent delta.dissociation, nas applied to heterogeneous equilibria, the transformati
39、on of one phase into two or more new phases, all ofdifferent composition. E7dynamic modulus,nsee complex modulus.elasticity, nthat property of materials that causes them to return to their original form or condition after the applied force isremoved. D4092elastic modulus,nsee complex modulus and sto
40、rage modulus.enthalpy, na thermodynamic function defined by the equation H = U + PV where H is the enthalpy, U is the internal energy,P is the pressure, and V the volume of the system.DISCUSSIONAt constant pressure the change in enthalpy measures the quantity of heat exchanged by the system and its
41、surrounding.equilibrium diagram,nsee constitutional diagram.eutectic point,nsee eutectic.eutectic, adjmixture of two or more substances which solidifies as a whole when cooled from the liquid state, without changein composition.E1142 124DISCUSSIONThe temperature at which the eutectic mixture solidif
42、ies is called the eutectic point. This temperature is constant for a given composition, and representsthe lowest melting point of the system.expansivity, nthe change in dimension resulting from an infinitesimal change in an independent variable (such as temperatureor humidity).failure, nthe point be
43、yond which a material ceases to be functionally capable of its intended use.failure temperature (Tf), nthe temperature at which a material fails.Fahrenheit, ndesignation of a degree on the Fahrenheit temperature scale that is related to the International PracticalTemperature Scale by means of the eq
44、uation: TF = 1.8 TC + 32.where:TF is the temperature in degree Fahrenheit and TC is the temperature in degrees Celsius.freezing temperature,nsee crystallization temperature.frequency, f, nthe number of cycles per unit time of periodic process.DISCUSSIONThe unit is Hertz (Hz) which is equal to 1 cycl
45、e per/s.frequency profile, nin dynamic mechanical measurement, plot of the dynamic properties of a material, at a constant temperature,as a function of test frequency. D4092gage pressure, npressure measured relative to atmospheric pressure.DISCUSSIONGage pressure is the difference between absolute p
46、ressure and atmospheric pressure.gamma () loss peak, nin dynamic mechanical measurement, third peak in the damping curve below the melt, in the order ofdecreasing temperature or increasing frequency. D4092Gibbs Phase Rule, nmaximum number of phases (P) that may coexist at equilibrium is equal to two
47、, plus the number ofcomponents (C) in the mixture, minus the number of degrees of freedom (F): P + F = C + 2. E7glass transition, nreversible change in an amorphous material or in amorphous regions of a partially crystalline material, from(or to) a viscous or rubbery condition to (or from) a hard an
48、d relatively brittle one.DISCUSSIONThe glass transition generally occurs over a relatively narrow temperature region and is similar to the solidification of a liquid to a glassy state. Notonly do hardness and brittleness undergo rapid changes in this temperature region, but other properties, such as
49、 coefficient of thermal expansion andspecific heat capacity, also change rapidly. This phenomenon sometimes is referred to as a second order transition, rubber transition, or rubberytransition. When more than one amorphous transition occurs in a material, the one associated with segmental motions of the backbone molecular chain,or accompanied by the largest change in properties is usually considered to be the glass transition
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