1、Designation: C1275 15C1275 16Standard 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 de
2、signation 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
3、determination of tensile behavior including tensile strength and stress-strain response undermonotonic uniaxial loading of continuous fiber-reinforced advanced ceramics at ambient temperature. This test method addresses,but is not restricted to, various suggested test specimen geometries as listed i
4、n the appendix. In addition, test specimen fabricationmethods, testing modes (force, displacement, or strain control), testing rates (force rate, stress rate, displacement rate, or strainrate), allowable bending, and data collection and reporting procedures are addressed. Note that tensile strength
5、as used in this testmethod refers to the tensile strength obtained under monotonic uniaxial loading where monotonic refers to a continuous nonstoptest rate with no reversals from test initiation to final fracture.1.2 This test method applies primarily to all advanced ceramic matrix composites with c
6、ontinuous fiber reinforcement:uni-directional (1-D), bi-directional (2-D), and tri-directional (3-D). In addition, this test method may also be used with glass(amorphous) matrix composites with 1-D, 2-D, and 3-D continuous fiber reinforcement. This test method does not address directlydiscontinuous
7、fiber-reinforced, whisker-reinforced or particulate-reinforced ceramics, although the test methods detailed here maybe equally applicable to these composites.1.3 Values expressed in this test method are in accordance with the International System of Units (SI) and IEEE/ASTM SI 10.1.4 This standard d
8、oes 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 establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. Specific hazard statements are give
9、n in Section 7 and 8.2.5.2.2. Referenced Documents2.1 ASTM Standards:2C1145 Terminology of Advanced CeramicsC1239 Practice for Reporting Uniaxial Strength Data and Estimating Weibull Distribution Parameters for Advanced CeramicsD3039/D3039M Test Method for Tensile Properties of Polymer Matrix Compos
10、ite MaterialsD3379 Test Method for Tensile Strength and Youngs Modulus 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 C
11、lassification of Extensometer SystemsE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE337 Test Method for Measuring Humidity with a Psychrometer (the Measurement of Wet- and Dry-Bulb Temperatures)E691 Practice for Conducting an Interlaboratory Study to Determine the Precisi
12、on of a Test MethodE1012 Practice for Verification of Testing Frame and Specimen Alignment Under Tensile and Compressive Axial ForceApplication1 This test method is under the jurisdiction of ASTM Committee C28 on Advanced Ceramics and is the direct responsibility of Subcommittee C28.07 on Ceramic Ma
13、trixComposites.Current edition approved July 1, 2015Dec. 1, 2016. Published September 2015January 2017. Originally approved in 1994. Last previous edition approved in 20102015as C1275 10.C1275 15. DOI: 10.1520/C1275-15.10.1520/C1275-16.2 For referencedASTM standards, visit theASTM website, www.astm.
14、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.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what chan
15、ges have been made to the previous version. Becauseit may not be technically possible 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 offic
16、ial document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1IEEE/ASTM SI 10 American National Standard for Use of the International System of Units (SI): The Modern Metric System3. Terminology3.1 Definitions:3.1.1 The definitions of
17、terms relating to tensile testing appearing in Terminology E6 apply to the terms used in this test method.The definitions of terms relating to advanced ceramics appearing in Terminology C1145 apply to the terms used in this test method.The definitions of terms relating to fiber-reinforced composites
18、 appearing in Terminology D3878 apply to the terms used in thistest method. Pertinent definitions as listed in Practice E1012, Terminology C1145, Terminology D3878, and Terminology E6 areshown in the following with the appropriate source given in parentheses.Additional terms used in conjunction with
19、 this test methodare defined in the following:3.1.2 advanced ceramic, nhighly engineered, high performance predominantly nonmetallic, inorganic, ceramic materialhaving specific functional attributes. C11453.1.3 axial strainaverage longitudinal strains measured at the surface on opposite sides of the
20、 longitudinal axis of symmetryof the specimen by two strain-sensing devices located at the mid length of the reduced section. E10123.1.4 bending straindifference between the strain at the surface and the axial strain. In general, the bending strain varies frompoint to point around and along the redu
21、ced section of the specimen. E10123.1.5 breaking forceforce at which fracture occurs. E63.1.6 ceramic matrix compositematerial consisting of two or more materials (insoluble in one another), in which the major,continuous component (matrix component) is a ceramic, while the secondary component/s (rei
22、nforcing component) may beceramic, glass-ceramic, glass, metal or organic in nature. These components are combined on a macroscale to form a usefulengineering material possessing certain properties or behavior not possessed by the individual constituents.3.1.7 continuous fiber-reinforced ceramic mat
23、rix composite (CFCC)ceramic matrix composite in which the reinforcing phaseconsists of a continuous fiber, continuous yarn, or a woven fabric.3.1.8 gage lengthoriginal length of that portion of the specimen over which strain or change of length is determined. E63.1.9 matrix-cracking stressapplied te
24、nsile stress at which the matrix cracks into a series of roughly parallel blocks normalto the tensile stress.3.1.10 DiscussionIn some cases, the matrix cracking stress may be indicated on the stress-strain curve by deviation fromlinearity (proportional limit) or incremental drops in the stress with
25、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 the unloading stress-strain (elastic limit).3.1.11 modulus of
26、 elasticityratio of stress to corresponding strain below the proportional limit. E63.1.12 modulus of resiliencestrain energy per unit volume required to elastically stress the material from zero to theproportional limit indicating the ability of the material to absorb energy when deformed elasticall
27、y and return it when unloaded.3.1.13 modulus of toughnessstrain energy per unit volume required to stress the material from zero to final fracture indicatingthe ability of the material to absorb energy beyond the elastic range (that is, damage tolerance of the material).3.1.14 Discussion The modulus
28、 of toughness can also be referred to as the cumulative damage energy and as such is regardedas an indication of the ability of the material to sustain damage rather than as a material property. Fracture mechanics methods forthe characterization of CFCCs have not been developed. The determination of
29、 the modulus of toughness as provided in this testmethod for the characterization of the cumulative damage process in CFCCs may become obsolete when fracture mechanicsmethods for CFCCs become available.3.1.15 proportional limit stressgreatest stress that a material is capable of sustaining without a
30、ny deviation fromproportionality of stress to strain (Hookes law).3.1.16 DiscussionMany experiments have shown that values observed for the proportional limit vary greatly with thesensitivity and accuracy of the testing equipment, eccentricity of loading, the scale to which the stress-strain diagram
31、 is plotted,and other factors. When determination of proportional limit is required, the procedure and sensitivity of the test equipment shouldbe specified. (See Terminology E6.)3.1.17 percent bendingbending strain times 100 divided by the axial strain. E10123.1.18 slow crack growthsubcritical crack
32、 growth (extension) which may result from, but is not restricted to, such mechanismsas environmentally-assisted stress corrosion or diffusive crack growth.3.1.19 tensile strengthmaximum tensile stress which a material is capable of sustaining. Tensile strength is calculated fromthe maximum load duri
33、ng a tension test carried to rupture and 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 generation.C1275 1624.2 Continuous fiber-reinforced
34、 ceramic matrix composites generally characterized by fine grain sized (65 %relative humidity (RH) is not recommended and any deviations from this recommendation must be reported.5.2 Surface preparation of test specimens, although normally not considered a major concern in CFCCs, can introducefabric
35、ation flaws that may have pronounced effects on tensile mechanical properties and behavior (for example, shape and levelof the resulting stress-strain curve, tensile strength and strain, proportional limit stress and strain, etc.). Machining damageintroduced during specimen preparation can be either
36、 a random interfering factor in the determination of ultimate strength ofpristine material (that is, increased frequency of surface initiated fractures compared to volume initiated fractures), or an inherentpart of the strength characteristics to be measured. Surface preparation can also lead to the
37、 introduction of residual stresses.Universal or standardized test methods of surface preparation do not exist. It should be understood that final machining steps may,or may not negate machining damage introduced during the initial machining. Thus, test specimen fabrication history may playan importa
38、nt role in the measured strength distributions and should be reported. In addition, the nature of fabrication used forcertain composites (for example, chemical vapor infiltration or hot pressing) may require the testing of test specimens in theas-processed condition (that is, it may not be possible
39、to machine the specimen faces).5.3 Bending in uniaxial tensile tests can cause or promote non-uniform stress distributions with maximum stresses occurringat the test specimen surface leading to non-representativenonrepresentative fractures originating at surfaces or near geometricaltransitions. In a
40、ddition, if deformations or strains are measured at surfaces where maximum or minimum stresses occur, bendingC1275 163may introduce over or under measurement of strains depending on the location of the strain-measuring device on the test specimen.Similarly, fracture from surface flaws may be accentu
41、ated or suppressed by the presence of the non-uniform stresses caused bybending.5.4 Fractures that initiate outside the uniformly-stressed gage section of a test specimen may be due to factors such as stressconcentrations or geometrical transitions, extraneous stresses introduced by gripping, or str
42、ength-limiting features in themicrostructure of the test specimen. Such non-gagenongage section fractures will normally constitute invalid tests. In addition, forface-loaded geometries, gripping pressure is a key variable in the initiation of fracture. Insufficient pressure can shear the outerplies
43、in laminated CFCCs; while too much pressure can cause local crushing of the CFCC and fracture in the vicinity of the grips.6. Apparatus6.1 Testing MachinesMachines used for tensile testing shall conform to the requirements of Practice E4. The force used indetermining tensile strength shall be accura
44、te within 61 % at any force within the selected force range of the testing machine asdefined in Practice E4. A schematic showing pertinent features of the tensile testing apparatus is shown in Fig. 1.6.2 Gripping Devices:6.2.1 GeneralVarious types of gripping devices may be used to transmit the meas
45、ured load applied by the testing machineto the test specimens. The brittle nature of the matrices of CFCCs requires a uniform interface between the grip components andthe gripped section of the specimen. Line or point contacts and non-uniform pressure can produce Hertizan-type stresses leadingto cra
46、ck initiation and fracture of the test specimen in the gripped section. Gripping devices can be classed generally as thoseemploying active and those employing passive grip interfaces as discussed in the following sections.6.2.2 Active Grip InterfacesActive grip interfaces require a continuous applic
47、ation of a mechanical, hydraulic, or pneumaticforce to transmit the load applied by the test machine to the test specimen. Generally, these types of grip interfaces cause a forceto be applied normal to the surface of the gripped section of the specimen. Transmission of the uniaxial force applied by
48、the testmachine is then accomplished by friction between the test specimen and the grip faces. Thus, important aspects of active gripinterfaces are uniform contact between the gripped section of the test specimen and the grip faces and constant coefficient offriction over the grip/specimen interface
49、.6.2.2.1 For flat test specimens, face-loaded grips, either by direct lateral pressure grip faces (1)3 or by indirect wedge-type gripfaces, act as the grip interface (2) as illustrated in Fig. 2 and Fig. 3, respectively. Generally, close tolerances are required for theflatness and parallelism as well as for the wedge angle of the wedge grip faces. In addition, the thickness, flatness, and parallelism3 The boldface numbers given in parentheses refer to a list of references at the end of the text.FIG. 1 Schematic Diagram of One Possible Apparatus for Condu
