ASTM_E_1461_-_13.pdf

Designation:E146113Standard Test Method forThermal Diffusivity by the Flash Method1This standard is issued under the fixed designation E1461;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 parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the thermaldiffusivity of primarily homogeneous isotropic solid materials.Thermal diffusivity values ranging from 0.1 to 1000(mm)2s-1are measurable by this test method from about 75 to 2800 K.1.2 Practice E2585 is adjunct to this test method andcontains detailed information regarding the use of the flashmethod.The two documents are complementing each other.1.3 This test method is a more detailed form of Test MethodC714,having applicability to much wider ranges of materials,applications,and temperatures,with improved accuracy ofmeasurements.1.4 This test method is intended to allow a wide variety ofapparatus designs.It is not practical in a test method of thistype to establish details of construction and procedures to coverall contingencies that might offer difficulties to a personwithout pertinent technical knowledge,or to restrict researchand development for improvements in the basic technique.1.5 This test method is applicable to the measurementsperformed on essentially fully dense(preferably,but lowporosity would be acceptable),homogeneous,and isotropicsolid materials that are opaque to the applied energy pulse.Experience shows that some deviation from these strict guide-lines can be accommodated with care and proper experimentaldesign,substantially broadening the usefulness of the method.1.6 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.7 For systems employing lasers as power sources,it isimperative that the safety requirement be fully met.1.8 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C714 Test Method for Thermal Diffusivity of Carbon andGraphite by Thermal Pulse MethodE228 Test Method for Linear Thermal Expansion of SolidMaterials With a Push-Rod DilatometerE2585 Practice for Thermal Diffusivity by the Flash Method3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 thermal conductivity,of a solid materialthe timerate of steady heat flow through unit thickness of an infiniteslab of a homogeneous material in a direction perpendicular tothe surface,induced by unit temperature difference.Theproperty must be identified with a specific mean temperature,since it varies with temperature.3.1.2 thermal diffusivity,of a solid materialthe propertygiven by the thermal conductivity divided by the product of thedensity and heat capacity per unit mass.3.2 Description of Symbols and Units Specific to ThisStandard:3.2.1 Ddiameter,m.3.2.2 Cpspecific heat capacity,Jg-1K-1.3.2.3 kconstant depending on percent rise.3.2.4 Kcorrection factors.3.2.5 K1,K2constants depending on.3.2.6 Lspecimen thickness,mm.3.2.7 tresponse time,s.3.2.8 t1/2half-rise time or time required for the rear facetemperature rise to reach one half of its maximum value,s.3.2.9 t*dimensionless time(t*=4st/DT2).3.2.10 Ttemperature,K.3.2.11 thermal diffusivity,(mm)2/s.3.2.12 fraction of pulse duration required to reach maxi-mum intensity.1This test method is under the jurisdiction ofASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.05 on Thermo-physical Properties.Current edition approved Sept.1,2013.Published October 2013.Originallyapproved in 1992.Last previous edition approved in 2011 as E1461 11.DOI:10.1520/E1461-13.2For referenced ASTM standards,visit the ASTM website,www.astm.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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.13 density,g/(cm)3.3.2.14 thermal conductivity,Wm-1K-1.3.2.15 t5T(5t12)/T(t12).3.2.16 t10T(10t12)/T(t12).3.2.17 Tmaxtemperature difference between baseline andmaximum rise,K.3.2.18 pulse duration(see Fig.1).3.3 Description of Subscripts Specific to This Standard:3.3.1 xpercent rise.3.3.2 Rratio.3.3.3 maxmaximum.3.3.4 pconstant pressure.4.Summary of Test Method4.1 A small,thin disc specimen is subjected to a high-intensity short duration radiant energy pulse(Fig.2).Theenergy of the pulse is absorbed on the front surface of thespecimen and the resulting rear face temperature rise(thermalcurve)is recorded.The therma