1、Designation: D3171 11Standard Test Methods forConstituent Content of Composite Materials1This standard is issued under the fixed designation D3171; 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 These test methods determine the constituent content ofcompo
3、site materials by one of two approaches. Test Method Iphysically removes the matrix by digestion or ignition by oneof seven procedures, leaving the reinforcement essentiallyunaffected and thus allowing calculation of reinforcement ormatrix content (by weight or volume) as well as percent voidvolume.
4、 Test Method II, applicable only to laminate materialsof known fiber areal weight, calculates reinforcement or matrixcontent (by weight or volume), and the cured ply thickness,based on the measured thickness of the laminate. Test MethodII is not applicable to the measurement of void volume.1.1.1 The
5、se test methods are primarily intended for two-partcomposite material systems. However, special provisions canbe made to extend these test methods to filled material systemswith more than two constituents, though not all test results canbe determined in every case.1.1.2 The procedures contained with
6、in have been designedto be particularly effective for certain classes of polymer ormetal matrices. The suggested applications are discussed inSection 4, as well as at the start of each procedure.1.1.3 Test Method I assumes that the reinforcement isessentially unaffected by the digestion or ignition
7、medium. Aprocedure for correction of the results for minor changes in thereinforcement is included. ProceduresAthrough F are based onchemical removal of the matrix while Procedure G removes thematrix by igniting the matrix in a furnace.1.1.4 Test Method II assumes that the fiber areal weight ofthe r
8、einforcement material form is known or controlled to anacceptable tolerance. The presence of voids is not measured.Eq 9 and 10 assume zero void content to perform thecalculation.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandar
9、d.1.3 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. See Section
10、9 foradditional information.2. Referenced Documents2.1 ASTM Standards:2D792 Test Methods for Density and Specific Gravity (Rela-tive Density) of Plastics by DisplacementD883 Terminology Relating to PlasticsD1505 Test Method for Density of Plastics by the Density-Gradient TechniqueD3878 Terminology f
11、or Composite MaterialsD5229/D5229M Test Method for Moisture AbsorptionProperties and Equilibrium Conditioning of Polymer Ma-trix Composite MaterialsE12 Terminology Relating to Density and Specific Gravityof Solids, Liquids, and Gases3E177 Practice for Use of the Terms Precision and Bias inASTM Test
12、MethodsE1309 Guide for Identification of Fiber-ReinforcedPolymer-Matrix Composite Materials in Databases3. Terminology3.1 DefinitionsTerminology D3878 defines terms relatingto composite materials. Terminology D883 defines termsrelating to plastics. Terminology E12 defines terms relating tospecific g
13、ravity. Practice E177 defines terms relating to statis-tics. In the event of a conflict between terms, TerminologyD3878 shall have precedence over other documents.3.1.1 fiber content, nthe amount of fiber present in acomposite or prepreg expressed either as percent by weight orpercent by volume. Thi
14、s is sometimes stated as a fraction. If nofillers exist, this is equivalent to reinforcement content.D38783.1.2 matrix content, nthe amount of matrix present in acomposite or prepreg expressed either as percent by weight or1These test methods are under the jurisdiction of ASTM Committee D30 onCompos
15、ite Materials and are the direct responsibility of Subcommittee D30.04 onLamina and Laminate Test Methods.Current edition approved Oct. 1, 2011. Published November 2011. Originallyapproved in 1973. Last previous edition approved in 2009 as D3171 09. DOI:10.1520/D3171-11.2For referenced ASTM standard
16、s, 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.3Withdrawn. The last approved version of this historical standard is referencedon www.astm
17、.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.percent by volume. For polymer matrix composites this is resincontent. D38783.1.3 reinforcement content, nthe amount of nonmatrixmaterial (fiber and filler) in a composite or prepr
18、eg expressedeither as percent by weight or percent by volume. D38783.1.4 resin content, nSee matrix content. D38783.1.5 void volume, nthe volume in the specimen withoutmass, that is identified as neither matrix nor reinforcement.D38783.2 Definitions of Terms Specific to This Standard:3.2.1 density,
19、r23Cthe weight per unit volume measuredin air, of the impermeable portion of a material at 23C.3.2.1.1 DiscussionThe definition of specific gravity anddensity are essentially equivalent to the definitions of apparentspecific gravity and apparent density in Terminology E12,because no correction is ma
20、de for buoyancy of the material inair. However, this difference is insignificant for most engineer-ing purposes.3.2.2 specific gravity, SG23Cthe ratio of the weight in airof a unit volume of the impermeable portion of a material at23C referenced to the standard unit volume weight of water at23C.3.3
21、Symbols:A = area of the specimen.Ar= calculated mass of one layer of reinforcement/unitarea.rc= density of the composite specimen.rm= density of the cured matrix.rr= density of the reinforcement or fiber.h = thickness of the specimen.hp= cured ply thickness, mm.Mc= mass of the dry crucible or sinter
22、ed glass filter.Mcr= mass of the dry crucible or sintered glass filter withreinforcement residue.Mi= initial mass of specimen before digestion or com-bustion.Mf= final mass of specimen after digestion or combus-tion.Np= number of plies in the laminate.Vm= volume percent of matrix in specimen.Vr= vol
23、ume percent of reinforcement in the specimen.Vv= void volume percent in the specimen.Wm= weight percent of matrix in the specimen.Wr= weight percent of reinforcement in the specimen.4. Summary of Test Method4.1 Test Method IThe matrix portion of a material speci-men of known mass is removed in a hot
24、 liquid medium (fordissolution) or furnace (for combustion). When dissolving in ahot liquid medium,the remaining residue, containing the rein-forcement, is then filtered, washed, dried, cooled, and weighed.The weight percent of the reinforcement is calculated, andfrom this value, and if densities of
25、 both the composite and thereinforcement are known, the volume percent is calculated. Anadditional calculation for void volume may be made if thedensity of the matrix is known or determined.4.1.1 Acorrection for weight change of the reinforcement orretention of the matrix may be made (13.3 and 13.4)
26、, if thischange is sufficiently reproducible under the conditions of thetest and has the same value for the reinforcement or matrixalone as for the constituents in the composite.4.1.1.1 Procedure A, for matrices such as epoxy resin, steel,copper, or others digestible by concentrated nitric acid.NOTE
27、 1Many reinforcements are attacked by nitric acid. If reinforce-ment is attacked, an alternative method is recommended, depending on thematrix. See Annex A1.4.1.1.2 Procedure B, for matrices such as epoxy, phenolic,polyamide, or thermoplastic resin, or others digestible by anaqueous mixture of sulfu
28、ric acid and hydrogen peroxide. SeeAnnex A2.4.1.1.3 Procedure C, for matrices such as epoxy resin andothers digestible by a mixture of ethylene glycol and potassiumhydroxide. See Annex A3.NOTE 2Procedure C is especially applicable to anhydride-curedepoxy systems containing aramid or carbon reinforce
29、ment.4.1.1.4 Procedure D, for matrices such as aluminum, brass,or others digestible by sodium hydroxide solution. See AnnexA4.4.1.1.5 Procedure E, for matrices such as steel, titanium,copper, aluminum, or others digestible by hydrochloric acid.See Annex A5.4.1.1.6 Procedure F, a version of Procedure
30、 A formicrowave-aided heating. See Annex A6.4.1.1.7 Procedure G, for reinforcements such as glass, orceramic that are not affected by high-temperature environ-ments, or reinforcements such as carbon where temperature isadequately controlled so that reinforcement does not char. SeeAnnex A7.4.2 Test M
31、ethod IIThe thickness of a relatively flat panelmade with reinforcement of known and consistent areal weightis measured. By the thickness of the panel, the reinforcementand matrix content is calculated.5. Significance and Use5.1 A constituent content of a composite material must beknown in order to
32、analytically model the material properties(mechanical, physical, thermal, or electrical) of the compositewhich are affected by the reinforcement or matrix. Also,knowledge of the constituent content is required for evaluationof the quality of a fabricated material and the processes usedduring fabrica
33、tion.5.2 The void volume of a composite material may signifi-cantly affect some of its mechanical properties. Higher voidvolumes usually mean lower fatigue resistance, greater suscep-tibility to moisture penetration and weathering, and increasedvariation or scatter in strength properties. Knowledge
34、of thevoid volume of a composite material is desirable as anindication of the quality of a composite.5.3 Reinforcement content may be used to normalize me-chanical properties affected by amount of reinforcement in thecoupon.6. Interferences6.1 Density of ConstituentsCalculation of the void vol-ume a
35、ssumes that reinforcement density and matrix densityobtained on a lot or material basis are held in the laminateD3171 112sample. There is a normal variation in reinforcement andmatrix densities that is dependent on the constituent material.This assumption used by the void calculation equations istyp
36、ically minor, changing the void calculation by less than0.2 %. One indication of this variation is the possibility ofobtaining a negative void volume in low-void volume compos-ites. If procedural errors can be ruled out, then it is reasonableto believe that constituent density variation is responsib
37、le.Negative void content is a physical impossibility, but apossibility in these calculations. It is useful to report negativevoid contents to assess if constituent density values areincorrect or within a typical range of material variation. Thenegative void value then sets an upper bound on error of
38、 thistest method for any material.6.2 Coupon SizeAbility to estimate void content is alsodetermined by coupon size and limitations of measuringapparatus. For example, with just limitations of the analyticalbalance (accurate to 0.2 mg), a coupon of 0.2 g with a voidvolume of 1.0 % would have an uncer
39、tainty of 10 % (reportedvoid volume in the range of 0.9 to 1.1 %) on the void volumecalculation as a result of possible balance error. A 1-g samplewould have an uncertainty of 2 % in the void volume calcula-tion (reported void volume in the range of 0.98 to 1.02 %)because of possible balance error f
40、or the same 1.0 % voidvolume.6.3 Error in Previous Measures4,5Ability to estimate voidcontent is also determined by the accuracy of previous mea-sures. Density measures of constituents and laminate havesome limitations. Good measures of these properties shouldhave an uncertainty of less than 0.0005
41、g/cm3. For a typicalcarbon/epoxy laminate, uncertainty in the void volume becauseof the limitation of the constituent density measurement wouldbe approximately 1 %.6.4 Mass Change of ReinforcementFibers may lose massby any of the techniques in Test Method I. This may beinvestigated by subjecting the
42、 reinforcement without matrix tothe test conditions of the composite. Once the technique isestablished for a material, no significant changes are expectedbetween samples unless the product or test conditions varysignificantly.6.5 Residual Matrix RetainedMatrix may be retained byany of the techniques
43、 of Test Method I. This may be investi-gated quantitatively by subjecting the matrix to the testconditions of the composite. Qualitatively, matrix appears ashardened pieces in the sample at the end of the test. Once thetechnique is established for a material, no significant changesare expected betwe
44、en samples unless the product or testconditions vary significantly.6.6 Micrometer InterfaceThe thickness of the laminatecontinuously changes, particularly for surfaces with a releasecloth or irregular surface. Test Method II measures the laminateat certain areas. The micrometer gives an indication o
45、f thethickness of the material at a point. The micrometer thicknessmeasure is dependent on (1) variation in thickness of the panel,(2) type and diameter of thickness measuring device, (3) abilityto hold panel perpendicular to the measurement device, and (4)sensitivity of the measurement device.6.6.1
46、 Ball micrometer geometry tends to give a thicknessmeasure for Test Method II that more closely approximatesfiber volume if there is a rough surface texture than a flat-facedmicrometer that tends to overstate laminate thickness. Forsome material forms, such as open weaves, the ball geometryis not pr
47、actical, so that a flat face micrometer is recommended.7. Apparatus7.1 General Requirements:7.1.1 Thermal ShockLaboratory equipment, which is sub-jected to nonambient temperatures (hot or cold), shall be oftempered glass or polytetrafluoroethylene (PTFE) materials.7.1.2 Post-Test Elemental AnalysisI
48、f a post-test elementalanalysis of the reinforcement residue is to be performed,laboratory equipment contacting the specimen shall be con-structed of PTFE, and specimen cutting performed only bydiamond-tipped tools.7.2 General Usage:7.2.1 Analytical BalanceThe analytical balance shall becapable of r
49、eading to within 60.1 mg.7.2.2 Laboratory Desiccator.7.3 Test Method I:7.3.1 Heating Equipment:7.3.1.1 Constant Heat SourceHeating mantle, hot plate,or controlled temperature bath, capable of heating material tothe required temperature for the particular digestion mediumand shall be capable of maintaining the temperature to 610C.7.3.1.2 Microwave, capable of maintaining a constant poweroutput. The microwave setup shall include an overpressurefail-safe device. Used exclusively for Procedure F (see AnnexA6).7.3.1.3 Drying Oven, air circulating, capable of
