1、Designation: D3171 11D3171 15Standard 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.
2、A number 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 U.S. Department of Defense.1. Scope1.1 These test methods determine the constituent co
3、ntent of composite materials by one of two approaches. Test Method Iphysically removes the matrix by digestion or ignition or carbonization by one of seveneight procedures, leaving the reinforcementessentially unaffected and thus allowing calculation of reinforcement or matrix content (by weight or
4、volume) as well as percentvoid volume. Test Method II, applicable only to laminate materials of 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 Method II isnot applicable to
5、the measurement of void volume.1.1.1 These test methods are primarily intended for two-part composite material systems. However, special provisions can bemade to extend these test methods to filled material systems with more than two constituents, though not all test results can bedetermined in ever
6、y case.1.1.2 The procedures contained within have been designed to be particularly effective for certain classes of polymer or metalmatrices. The suggested applications are discussed in Section 4, as well as at the start of each procedure.1.1.3 Test Method I assumes that the reinforcement is essenti
7、ally unaffected by the digestion or ignition medium. medium orcarbonization. A procedure for correction of the results for minor changes in the reinforcement is included. Procedures A throughF are based on chemical removal of the matrix while Procedure G removes the matrix by igniting the matrix in
8、a furnace. ProcedureH carbonizes the matrix in a furnace.1.1.4 Test Method II assumes that the fiber areal weight of the reinforcement material form is known or controlled to anacceptable tolerance. The presence of voids is not measured. Eq 915 and 1016 assume zero void content to perform the calcul
9、ation.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to estab
10、lish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. See Section 9 for additional information.2. Referenced Documents2.1 ASTM Standards:2D792 Test Methods for Density and Specific Gravity (Relative Density) of Plastics by DisplacementD88
11、3 Terminology Relating to PlasticsD1505 Test Method for Density of Plastics by the Density-Gradient TechniqueD3878 Terminology for Composite MaterialsD5229/D5229M Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Matrix CompositeMaterialsE12 Terminology Relating
12、to Density and Specific Gravity of Solids, Liquids, and Gases (Withdrawn 1996)3E177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE1309 Guide for Identification of Fiber-Reinforced Polymer-Matrix Composite Materials in Databases1 These test methods are under the jurisdiction o
13、f ASTM Committee D30 on Composite Materials and are the direct responsibility of Subcommittee D30.04 on Laminaand Laminate Test Methods.Current edition approved Oct. 1, 2011April 1, 2015. Published November 2011May 2015. Originally approved in 1973. Last previous edition approved in 20092011 asD3171
14、 09.D3171 11. DOI: 10.1520/D3171-11.10.1520/D3171-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The la
15、st approved version of this historical standard is referenced on www.astm.org.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 to adequate
16、ly 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 Conshohocken,
17、 PA 19428-2959. United States13. Terminology3.1 DefinitionsTerminology D3878 defines terms relating to composite materials. Terminology D883 defines terms relatingto plastics. Terminology E12 defines terms relating to specific gravity. Practice E177 defines terms relating to statistics. In the event
18、of a conflict between terms, Terminology D3878 shall have precedence over other documents.3.1.1 fiber content, nthe amount of fiber present in a composite or prepreg expressed either as percent by weight or percentby volume. This is sometimes stated as a fraction. If no fillers exist, this is equiva
19、lent to reinforcement content. D38783.1.2 matrix content, nthe amount of matrix present in a composite or prepreg expressed either as percent by weight or percentby volume. For polymer matrix composites this is resin content. D38783.1.3 reinforcement content, nthe amount of nonmatrix material (fiber
20、 and filler) in a composite or prepreg expressed eitheras 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 without mass, that is identified as neither matrix nor reinforcement. D38783.2 Definitions of Terms Spe
21、cific to This Standard:3.2.1 density, 23Cthe weight per unit volume measured in air, of the impermeable portion of a material at 23C.3.2.1.1 DiscussionThe definition of specific gravity and density are essentially equivalent to the definitions of apparent specific gravity and apparentdensity in Term
22、inology E12, because no correction is made for buoyancy of the material in air. However, this difference isinsignificant for most engineering purposes.3.2.2 specific gravity, SG23Cthe ratio of the weight in air of a unit volume of the impermeable portion of a material at 23Creferenced to the standar
23、d unit volume weight of water at 23C.3.3 Symbols:A = area of the specimen.Ar = calculated mass of one layer of reinforcement/unit area.CR = carbonization ratio of the neat resinc = density of the composite specimen.m = density of the cured matrix.r = density of the reinforcement or fiber.h = thickne
24、ss of the specimen.hp = cured ply thickness, mm.mc = mass of the dry crucible for neat resin carbonizationmcr = mass of the dry crucible with carbonized neat resinmd = final mass of the neat resin residue after carbonizationmi = initial mass of the neat resin specimenMc = mass of the dry crucible or
25、 sintered glass filter.Mcr = mass of the dry crucible or sintered glass filter with reinforcement residue.Md = final residue mass of the composite specimenMi = initial mass of specimen before digestion or combustion.Mf = final mass of specimen after digestion or combustion.Mm = mass of the resin mat
26、rix in the composite specimenNp = number of plies in the laminate.Vm = volume percent of matrix in specimen.Vr = volume 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
27、.4. Summary of Test Method4.1 Test Method IThe matrix portion of a material specimen of known mass is removed in a hot liquid medium (fordissolution) or furnace (for combustion). When dissolving in a hot liquid medium,the medium, the remaining residue, containingthe reinforcement, is then filtered,
28、washed, dried, cooled, and weighed. The weight percent of the reinforcement is calculated, andfrom this value, and if densities of both the composite and the reinforcement are known, the volume percent is calculated. Anadditional calculation for void volume may be made if the density of the matrix i
29、s known or determined.4.1.1 Acorrection for weight change of the reinforcement or retention of the matrix may be made (13.3(13.1.2 and 13.1.313.4),),if this change is sufficiently reproducible under the conditions of the test and has the same value for the reinforcement or matrixalone as for the con
30、stituents in the composite.D3171 1524.1.1.1 Procedure A, for matrices such as epoxy resin, steel, copper, or others digestible by concentrated nitric acid.NOTE 1Many reinforcements are attacked by nitric acid. If reinforcement is attacked, an alternative method is recommended, depending on thematrix
31、. See Annex A1.4.1.1.2 Procedure B, for matrices such as epoxy, phenolic, polyamide, or thermoplastic resin, or others digestible by an aqueousmixture of sulfuric acid and hydrogen peroxide. See Annex A2.4.1.1.3 Procedure C, for matrices such as epoxy resin and others digestible by a mixture of ethy
32、lene glycol and potassiumhydroxide. See Annex A3.NOTE 2Procedure C is especially applicable to anhydride-cured epoxy systems containing aramid or carbon reinforcement.4.1.1.4 Procedure D, for matrices such as aluminum, brass, or others digestible by sodium hydroxide solution. See Annex A4.4.1.1.5 Pr
33、ocedure E, for matrices such as steel, titanium, copper, aluminum, or others digestible by hydrochloric acid. SeeAnnex A5.4.1.1.6 Procedure F, a version of Procedure A for microwave-aided heating. See Annex A6.4.1.1.7 Procedure G, for reinforcements such as glass, or ceramic that are not affected by
34、 high-temperature environments, orreinforcements such as carbon where temperature is adequately controlled so that reinforcement does not char. See Annex A7.4.1.1.8 Procedure H, for any reinforcements, particularly carbon, that are not affected at high temperature in a nitrogenatmosphere, and any re
35、sin matrix systems.The correction for the retention of the matrix (13.1.3) is not necessary for this procedure.See Annex A8.4.2 Test Method IIThe thickness of a relatively flat panel made with reinforcement of known and consistent areal weight ismeasured. By the thickness of the panel, the reinforce
36、ment and matrix content is calculated.5. Significance and Use5.1 A constituent content of a composite material must be known in order to analytically model the material properties(mechanical, physical, thermal, or electrical) of the composite which are affected by the reinforcement or matrix.Also, k
37、nowledgeof the constituent content is required for evaluation of the quality of a fabricated material and the processes used during fabrication.5.2 The void volume of a composite material may significantly affect some of its mechanical properties. Higher void volumesusually mean lower fatigue resist
38、ance, greater susceptibility to moisture penetration and weathering, and increased variation orscatter in strength properties. Knowledge of the void volume of a composite material is desirable as an indication of the qualityof a composite.5.3 Reinforcement content may be used to normalize mechanical
39、 properties affected by amount of reinforcement in the coupon.6. Interferences6.1 Density of ConstituentsCalculation of the void volume assumes that reinforcement density and matrix density obtainedon a lot or material basis are held in the laminate sample. There is a normal variation in reinforceme
40、nt and matrix densities thatis dependent on the constituent material. This assumption used by the void calculation equations is typically minor, changing thevoid calculation by less than 0.2 %. One indication of this variation is the possibility of obtaining a negative void volume inlow-void volume
41、composites. If procedural errors can be ruled out, then it is reasonable to believe that constituent density variationis responsible. Negative void content is a physical impossibility, but a possibility in these calculations. It is useful to report negativevoid contents to assess if constituent dens
42、ity values are incorrect or within a typical range of material variation. The negative voidvalue then sets an upper bound on error of this test method for any material.6.2 Coupon SizeAbility to estimate void content is also determined by coupon size and limitations of measuring apparatus.For example
43、, with just limitations of the analytical balance (accurate to 0.2 mg), a coupon of 0.2 g with a void volume of 1.0 %would have an uncertainty of 10 % (reported void volume in the range of 0.9 to 1.1 %) on the void volume calculation as a resultof possible balance error. A 1-g sample would have an u
44、ncertainty of 2 % in the void volume calculation (reported void volumein the range of 0.98 to 1.02 %) because of possible balance error for the same 1.0 % void volume.6.3 Error in Previous Measures4,5Ability to estimate void content is also determined by the accuracy of previous measures.Density mea
45、sures of constituents and laminate have some limitations. Good measures of these properties should have anuncertainty of less than 0.0005 g/cm3. For a typical carbon/epoxy laminate, uncertainty in the void volume because of the limitationof the constituent density measurement would be approximately
46、1 %.6.4 Mass Change of ReinforcementFibers may lose mass by any of the techniques in Test Method I. This may be investigatedby subjecting the reinforcement without matrix to the test conditions of the composite. Once the technique is established for amaterial, no significant changes are expected bet
47、ween samples unless the product or test conditions vary significantly.4 The interface region in glass fiber-reinforced epoxy resin composites: 1. Sample Preparation, Void Content and Interfacial Strength,Composites , 26, 1995, pp. 467475.5 “A Comparison of Void Measurement Methods for Carbon/Epoxy C
48、omposites,” U.S. Army Materials Technology Laboratory (US Army Research Laboratory) MTLTR9113.D3171 1536.5 Residual Matrix RetainedMatrix may be retained by any of the techniques of Test Method I. This may be investigatedquantitatively by subjecting the matrix to the test conditions of the composite
49、. Qualitatively, matrix appears as hardened pieces inthe sample at the end of the test. Once the technique is established for a material, no significant changes are expected betweensamples unless the product or test conditions vary significantly.6.6 Micrometer InterfaceThe thickness of the laminate continuously changes, particularly for surfaces with a release cloth orirregular surface. Test Method II measures the laminate at certain areas. The micrometer gives an indication of the thickness ofthe material at a point. The micrometer thickness meas
