1、Designation: C1275 10Standard Test Method forMonotonic Tensile Behavior of Continuous Fiber-ReinforcedAdvanced Ceramics with Solid Rectangular Cross-SectionTest Specimens at Ambient Temperature1This standard is issued under the fixed designation C1275; the number immediately following the designatio
2、n 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 determin
3、ation of tensilebehavior including tensile strength and stress-strain responseunder monotonic uniaxial loading of continuous fiber-reinforced advanced ceramics at ambient temperature. This testmethod addresses, but is not restricted to, various suggestedtest specimen geometries as listed in the appe
4、ndix. In addition,test specimen fabrication methods, testing modes (force, dis-placement, or strain control), testing rates (force rate, stressrate, displacement rate, or strain rate), allowable bending, anddata collection and reporting procedures are addressed. Notethat tensile strength as used in
5、this test method refers to thetensile strength obtained under monotonic uniaxial loadingwhere monotonic refers to a continuous nonstop test rate withno reversals from test initiation to final fracture.1.2 This test method applies primarily to all advancedceramic matrix composites with continuous fib
6、er reinforce-ment: uni-directional (1-D), bi-directional (2-D), and tri-directional (3-D). In addition, this test method may also beused with glass (amorphous) matrix composites with 1-D, 2-D,and 3-D continuous fiber reinforcement. This test method doesnot address directly discontinuous fiber-reinfo
7、rced, whisker-reinforced or particulate-reinforced ceramics, although the testmethods detailed here may be equally applicable to thesecomposites.1.3 Values expressed in this test method are in accordancewith the International System of Units (SI) and IEEE/ASTM SI10 .1.4 This standard does not purpor
8、t 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. Specific hazardstatements are given in Section
9、7 and 8.2.5.2.2. Referenced Documents2.1 ASTM Standards:2C1145 Terminology of Advanced CeramicsC1239 Practice for Reporting Uniaxial Strength Data andEstimating Weibull Distribution Parameters for AdvancedCeramicsD3039/D3039M Test Method for Tensile Properties ofPolymer Matrix Composite MaterialsD33
10、79 Test Method for Tensile Strength and YoungsModulus for High-Modulus Single-Filament MaterialsD3878 Terminology for Composite MaterialsE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE83 Practice for Verification and Classification of
11、Exten-someter SystemsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE337 Test Method for Measuring Humidity with a Psy-chrometer (the Measurement of Wet- and Dry-Bulb Tem-peratures)E691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Met
12、hodE1012 Practice for Verification of Test Frame and SpecimenAlignment Under Tensile and Compressive Axial ForceApplicationIEEE/ASTM SI 10 American National Standard for Use ofthe International System of Units (SI): The Modern MetricSystem3. Terminology3.1 DefinitionsThe definitions of terms relatin
13、g to tensiletesting appearing in Terminology E6 apply to the terms used inthis test method. The definitions of terms relating to advancedceramics appearing in Terminology C1145 apply to the termsused in this test method. The definitions of terms relating tofiber-reinforced composites appearing in Te
14、rminology D38781This test method is under the jurisdiction of ASTM Committee C28 onAdvanced Ceramics and is the direct responsibility of Subcommittee C28.07 onCeramic Matrix Composites.Current edition approved Dec. 1, 2010. Published January 2011. Originallyapproved in 1994. Last previous edition ap
15、proved in 2005 as C1275 00 (2005)1.DOI: 10.1520/C1275-10.2For 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.1Cop
16、yright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.apply to the terms used in this test method. Pertinent definitionsas listed in Practice E1012, Terminology C1145, TerminologyD3878, and Terminology E6 are shown in the following withthe app
17、ropriate source given in parentheses. Additional termsused in conjunction with this test method are defined in thefollowing:3.1.1 advanced ceramic, nhighly engineered, high perfor-mance predominantly nonmetallic, inorganic, ceramic materialhaving specific functional attributes. C11453.1.2 axial stra
18、inaverage longitudinal strains measured atthe surface on opposite sides of the longitudinal axis ofsymmetry of the specimen by two strain-sensing deviceslocated at the mid length of the reduced section. E10123.1.3 bending straindifference between the strain at thesurface and the axial strain. In gen
19、eral, the bending strainvaries from point to point around and along the reduced sectionof the specimen. E10123.1.4 breaking forceforce at which fracture occurs. E63.1.5 ceramic matrix compositematerial consisting of twoor more materials (insoluble in one another), in which themajor, continuous compo
20、nent (matrix component) is a ceramic,while the secondary component/s (reinforcing component) maybe ceramic, glass-ceramic, glass, metal or organic in nature.These components are combined on a macroscale to form auseful engineering material possessing certain properties orbehavior not possessed by th
21、e individual constituents.3.1.6 continuous fiber-reinforced ceramic matrix composite(CFCC)ceramic matrix composite in which the reinforcingphase consists of a continuous fiber, continuous yarn, or awoven fabric.3.1.7 gage lengthoriginal length of that portion of thespecimen over which strain or chan
22、ge of length is determined.E63.1.8 matrix-cracking stressapplied tensile stress atwhich the matrix cracks into a series of roughly parallel blocksnormal to the tensile stress.3.1.9 DiscussionIn some cases, the matrix cracking stressmay be indicated on the stress-strain curve by deviation fromlineari
23、ty (proportional limit) or incremental drops in the stresswith increasing strain. In other cases, especially with materialswhich do not possess a linear portion of the stress-strain curve,the matrix cracking stress may be indicated as the first stress atwhich a permanent offset strain is detected in
24、 the unloadingstress-strain (elastic limit).3.1.10 modulus of elasticityratio of stress to correspond-ing strain below the proportional limit. E63.1.11 modulus of resiliencestrain energy per unit vol-ume required to elastically stress the material from zero to theproportional limit indicating the ab
25、ility of the material toabsorb energy when deformed elastically and return it whenunloaded.3.1.12 modulus of toughnessstrain energy per unit volumerequired to stress the material from zero to final fractureindicating the ability of the material to absorb energy beyondthe elastic range (that is, dama
26、ge tolerance of the material).3.1.13 Discussion The modulus of toughness can also bereferred to as the cumulative damage energy and as such isregarded as an indication of the ability of the material to sustaindamage rather than as a material property. Fracture mechanicsmethods for the characterizati
27、on of CFCCs have not beendeveloped. The determination of the modulus of toughness asprovided in this test method for the characterization of thecumulative damage process in CFCCs may become obsoletewhen fracture mechanics methods for CFCCs become avail-able.3.1.14 proportional limit stressgreatest s
28、tress that a ma-terial is capable of sustaining without any deviation fromproportionality of stress to strain (Hookes law).3.1.15 DiscussionMany experiments have shown thatvalues observed for the proportional limit vary greatly with thesensitivity and accuracy of the testing equipment, eccentricityo
29、f loading, the scale to which the stress-strain diagram isplotted, and other factors. When determination of proportionallimit is required, the procedure and sensitivity of the testequipment should be specified. (See Terminology E6.)3.1.16 percent bendingbending strain times 100 dividedby the axial s
30、train. E10123.1.17 slow crack growthsubcritical crack growth (exten-sion) which may result from, but is not restricted to, suchmechanisms as environmentally-assisted stress corrosion ordiffusive crack growth.3.1.18 tensile strengthmaximum tensile stress which amaterial is capable of sustaining. Tens
31、ile strength is calculatedfrom the maximum load during a tension test carried to ruptureand the original cross-sectional area of the specimen. E64. Significance and Use4.1 This test method may be used for material development,material comparison, quality assurance, characterization, anddesign data g
32、eneration.4.2 Continuous fiber-reinforced ceramic matrix compositesgenerally characterized by fine grain sized (65 % relative humidity (RH) is not recommended and anydeviations from this recommendation must be reported.5.2 Surface preparation of test specimens, although nor-mally not considered a ma
33、jor concern in CFCCs, can introducefabrication flaws that may have pronounced effects on tensilemechanical properties and behavior (for example, shape andlevel of the resulting stress-strain curve, tensile strength andstrain, proportional limit stress and strain, etc.). Machiningdamage introduced du
34、ring specimen preparation can be eithera random interfering factor in the determination of ultimatestrength of pristine material (that is, increased frequency ofsurface initiated fractures compared to volume initiated frac-tures), or an inherent part of the strength characteristics to bemeasured. Su
35、rface preparation can also lead to the introductionof residual stresses. Universal or standardized test methods ofsurface preparation do not exist. It should be understood thatfinal machining steps may, or may not negate machiningdamage introduced during the initial machining. Thus, testspecimen fab
36、rication history may play an important role in themeasured strength distributions and should be reported. Inaddition, the nature of fabrication used for certain composites(for example, chemical vapor infiltration or hot pressing) mayrequire the testing of test specimens in the as-processedcondition
37、(that is, it may not be possible to machine thespecimen faces).5.3 Bending in uniaxial tensile tests can cause or promotenon-uniform stress distributions with maximum stresses occur-ring at the test specimen surface leading to non-representativefractures originating at surfaces or near geometrical t
38、ransitions.In addition, if deformations or strains are measured at surfaceswhere maximum or minimum stresses occur, bending mayintroduce over or under measurement of strains depending onthe location of the strain-measuring device on the test speci-men. Similarly, fracture from surface flaws may be a
39、ccentuatedor suppressed by the presence of the non-uniform stressescaused by bending.5.4 Fractures that initiate outside the uniformly-stressedgage section of a test specimen may be due to factors such asstress concentrations or geometrical transitions, extraneousstresses introduced by gripping, or
40、strength-limiting features inthe microstructure of the test specimen. Such non-gage sectionfractures will normally constitute invalid tests. In addition, forface-loaded geometries, gripping pressure is a key variable inthe initiation of fracture. Insufficient pressure can shear theouter plies in lam
41、inated CFCCs; while too much pressure cancause local crushing of the CFCC and fracture in the vicinity ofthe grips.6. Apparatus6.1 Testing MachinesMachines used for tensile testingshall conform to the requirements of Practice E4. The forceused in determining tensile strength shall be accurate within
42、61 % at any force within the selected force range of the testingmachine as defined in Practice E4. A schematic showingpertinent features of the tensile testing apparatus is shown inFig. 1.6.2 Gripping Devices:6.2.1 GeneralVarious types of gripping devices may beused to transmit the measured load app
43、lied by the testingmachine to the test specimens. The brittle nature of thematrices of CFCCs requires a uniform interface between thegrip components and the gripped section of the specimen. Lineor point contacts and non-uniform pressure can produceHertizan-type stresses leading to crack initiation a
44、nd fracture ofthe test specimen in the gripped section. Gripping devices canbe classed generally as those employing active and thoseemploying passive grip interfaces as discussed in the followingsections.C1275 1036.2.2 Active Grip InterfacesActive grip interfaces requirea continuous application of a
45、 mechanical, hydraulic, or pneu-matic force to transmit the load applied by the test machine tothe test specimen. Generally, these types of grip interfacescause a force to be applied normal to the surface of the grippedsection of the specimen. Transmission of the uniaxial forceapplied by the test ma
46、chine is then accomplished by frictionbetween the test specimen and the grip faces. Thus, importantaspects of active grip interfaces are uniform contact betweenthe gripped section of the test specimen and the grip faces andconstant coefficient of friction over the grip/specimen inter-face.6.2.2.1 Fo
47、r flat test specimens, face-loaded grips, either bydirect lateral pressure grip faces (1)3or by indirect wedge-typegrip faces, act as the grip interface (2) as illustrated in Fig. 2and Fig. 3, respectively. Generally, close tolerances are re-quired for the flatness and parallelism as well as for the
48、 wedgeangle of the wedge grip faces. In addition, the thickness,flatness, and parallelism of the gripped section of the testspecimen must be within similarly close tolerances to promoteuniform contact at the test specimen/grip interface. Toleranceswill vary depending on the exact configuration as sh
49、own in theappropriate test specimen drawings.6.2.2.2 Sufficient lateral pressure must be applied to preventslippage between the grip face and the test specimen. Gripsurfaces that are scored or serrated with a pattern similar to thatof a single-cut file have been found satisfactory. A fineserration appears to be the most satisfactory. The serrationsshould be kept clean and well defined but not overly sharp. Thelength and width of the grip faces should be equal to or greaterthan the respective length and width of the gripped sections ofthe test specimen.6.2.3
