1、Designation: C 1358 05Standard Test Method forMonotonic Compressive Strength Testing of ContinuousFiber-Reinforced Advanced Ceramics with Solid RectangularCross-Section Test Specimens at Ambient Temperatures1This standard is issued under the fixed designation C 1358; the number immediately following
2、 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method cov
3、ers the determination of compres-sive strength including stress-strain behavior under monotonicuniaxial loading of continuous fiber-reinforced advanced ce-ramics at ambient temperatures. This test method addresses,but is not restricted to, various suggested test specimengeometries as listed in the a
4、ppendix. In addition, test specimenfabrication methods, testing modes (force, displacement, orstrain control), testing rates (force rate, stress rate, displace-ment rate, or strain rate), allowable bending, and data collec-tion and reporting procedures are addressed. Compressivestrength as used in t
5、his test method refers to the compressivestrength obtained under monotonic uniaxial loading wheremonotonic refers to a continuous nonstop test rate with noreversals from test initiation to final fracture.1.2 This test method applies primarily to advanced ceramicmatrix composites with continuous fibe
6、r reinforcement: uni-directional (1D), bi-directional (2D), and tri-directional(3D) or other multi-directional reinforcements. In addition,this test method may also be used with glass (amorphous)matrix composites with 1D, 2D, 3D, and other multi-directional continuous fiber reinforcements. This test
7、 methoddoes not directly address discontinuous fiber-reinforced,whisker-reinforced, or particulate-reinforced ceramics, al-though the test methods detailed here may be equally appli-cable to these composites.1.3 The values stated in SI units are to be regarded as thestandard and are in accordance wi
8、th SI 10-02 IEEE/ASTM SI10.1.4 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 p
9、rior to use. Refer to Section 7for specific precautions.2. Referenced Documents2.1 ASTM Standards:2C 1145 Terminology of Advanced CeramicsD 695 Test Method for Compressive Properties of RigidPlasticsD 3379 Test Method for Tensile Strength and YoungsModulus for High-Modulus Single-Filament MaterialsD
10、 3410/D 3410M Test Method for Compressive Propertiesof Polymer Matrix Composite MaterialsWith UnsupportedGage Section by Shear LoadingD 3479/D 3479M Test Method for Tension-Tension Fatigueof Polymer Matrix Composite MaterialsD 3878 Terminology for Composite MaterialsE4 Practices for Force Verificati
11、on of Testing MachinesE6 Terminology Relating to Methods of Mechanical Test-ingE83 Practice for Verification and Classification of Exten-someter SystemE 337 Test Method for Measuring Humidity with Psychom-eter (the Measurement ofWet-and Dry-BulbTemperatures)E 1012 Practice for Verification of Specim
12、en AlignmentUnder Tensile LoadingSI 10-02 IEEE/ASTM SI 10 American National Standardfor Use of the International System of Units (SI): TheModern Metric System3. Terminology3.1 Definitions:3.1.1 The definitions of terms relating to compressive test-ing, advanced ceramics, and fiber-reinforced composi
13、tes, ap-pearing in Terminology E6, Test Method D 695, PracticeE 1012, Terminology C 1145, Test Method D 3410/D 3410M,and Terminology D 3878 apply to the terms used in this testmethod. Pertinent definitions are shown as follows with theappropriate source given in parentheses.Additional terms usedin c
14、onjunction with this test method are defined in 3.2.1This 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 June 1, 2005. Published July 2005. Originally approve
15、din 1996. Last previous edition approved in 2000 as C 1358 96 (2000),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
16、website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2 Definitions of Terms Specific to This Standard:3.2.1 advanced ceramic, nhighly engineered, high-performance predominantly non-metallic, inorganic, ceramicmaterial having spe
17、cific functional attributes. C 11453.2.2 axial strain LL1, naverage longitudinal strainsmeasured at the surface on opposite sides of the longitudinalaxis of symmetry of the specimen by two strain-sensingdevices located at the mid length of the reduced section.E 10123.2.3 bending strain LL1, ndiffere
18、nce between thestrain at the surface and the axial strain. In general, the bendingstrain varies from point to point around and along the reducedsection of the specimen. E 10123.2.4 breaking force F, nforce at which fracture occurs.E63.2.5 ceramic matrix composite, nmaterial consisting oftwo or more
19、materials (insoluble in one another), in which themajor, continuous component (matrix component) is a ceramic,while the secondary component(s) (reinforcing component)may be ceramic, glass-ceramic, glass, metal, or organic innature. These components are combined on a macroscale toform a useful engine
20、ering material possessing certain proper-ties or behavior not possessed by the individual constituents.3.2.6 compressive strength FL2, nmaximum compres-sive stress which a material is capable of sustaining. Compres-sive strength is calculated from the maximum force during acompression test carried t
21、o rupture and the original cross-sectional area of the specimen. E63.2.7 continuous fiber-reinforced ceramic matrix composite(CFCC), nceramic matrix composite in which the reinforc-ing phase consists of a continuous fiber, continuous yarn, or awoven fabric.3.2.8 gage length L, noriginal length of th
22、at portion ofthe specimen over which strain or change of length is deter-mined. E63.2.9 modulus of elasticity FL2, nratio of stress tocorresponding strain below the proportional limit. E63.2.10 proportional limit stress in compression FL2,ngreatest stress that a material is capable of sustainingwith
23、out any deviation from proportionality of stress to strain(Hookes law).3.2.10.1 DiscussionMany experiments have shown thatvalues observed for the proportional limit vary greatly with thesensitivity and accuracy of the testing equipment, eccentricityof loading, the scale to which the stress-strain di
24、agram isplotted, and other factors. When determination of proportionallimit is required, specify the procedure and sensitivity of thetest equipment. E63.2.11 percent bending, nbending strain times 100 di-vided by the axial strain. E 10123.2.12 slow crack growth (SCG), nsubcritical crackgrowth (exten
25、sion) which may result from, but is not restrictedto, such mechanisms as environmentally-assisted stress corro-sion or diffusive crack growth. C 11454. Significance and Use4.1 This test method may be used for material development,material comparison, quality assurance, characterization, reli-ability
26、 assessment, and design data generation.4.2 Continuous fiber-reinforced ceramic matrix composites(CFCCs) are generally characterized by fine-grain sized (65 % relative humidity (RH) is notrecommended.5.2 Surface preparation of test specimens, although nor-mally not considered a major concern in CFCC
27、s, can introducefabrication flaws that may have pronounced effects on com-pressive mechanical properties and behavior (for example,shape and level of the resulting stress-strain curve, compres-sive strength and strain, proportional limit stress and strain,etc.) Machining damage introduced during tes
28、t specimenpreparation can be either a random interfering factor in thedetermination of ultimate strength of pristine material (that is,increased frequency of surface-initiated fractures compared tovolume-initiated fractures), or an inherent part of the strengthcharacteristics to be measured. Surface
29、 preparation can alsolead to the introduction of residual stresses. Universal orstandardized test methods of surface preparation do not exist.In addition, the nature of fabrication used for certain compos-ites (for example, chemical vapor infiltration or hot pressing)may require the testing of test
30、specimens in the as-processedcondition (that is, it may not be possible to machine the testspecimen faces without compromising the in-plane fiber archi-tecture). Final machining steps may, or may not, negatemachining damage introduced during the initial machining.Thus, report test specimen fabricati
31、on history since it may playan important role in the measured strength distributions.5.3 Bending in uniaxial compressive tests can introduceeccentricity leading to geometric instability of the test speci-men and buckling failure before true compressive strength isattained. In addition, if deformatio
32、ns or strains are measured atsurfaces where maximum or minimum stresses occur, bendingmay introduce over or under measurement of strains dependingon the location of the strain-measuring device on the testspecimen. Bending can be introduced from, among othersources, initial load train misalignment, m
33、isaligned test speci-mens as installed in the grips, warped test specimens, or loadtrain misalignment introduced during testing due to low lateralmachine/grip stiffness.5.4 Fractures that initiate outside the uniformly stressedgage section of a test specimen may be due to factors such asstress conce
34、ntrations or geometrical transitions, extraneousstresses introduced by gripping, or strength-limiting features inthe microstructure of the test specimen. Such non-gage sectionfractures will normally constitute invalid tests. In addition, forfrictional face-loaded geometrics, gripping pressure is a k
35、eyvariable in the initiation of fracture. Insufficient pressure canshear the outer plies in laminated CFCCs; while too muchpressure can cause local crushing of the CFCC and may initiatefracture in the vicinity of the grips.5.5 Lateral supports are sometimes used in compressiontests to reduce the ten
36、dency of test specimen buckling. How-ever, such lateral supports may introduce sufficient frictionalstress so as to artificially increase the force required to producecompressive failure. In addition, the lateral supports andattendant frictional stresses may invalidate the assumption ofuniaxial stre
37、ss state. When lateral supports are used, thefrictional effect should be quantified to ensure that its contri-bution is small, and the means for doing so reported along withthe quantity of the frictional effect.6. Apparatus6.1 Testing Machines Machines used for compressivetesting shall conform to Pr
38、actices E4. The forces used indetermining compressive strength shall be accurate within61 % at any force within the selected load range of the testingmachine as defined in Practices E4. A schematic showingpertinent features of one possible compressive testing appara-tus is shown in Fig. 1.6.2 Grippi
39、ng Devices:6.2.1 GeneralVarious types of gripping devices may beused to transmit the measured force applied 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 test specimen.Lin
40、e or point contacts and nonuniform pressure can produceHertzian-type stresses leading to crack initiation and fracture ofthe test specimen in the gripped section.6.2.1.1 The primary recommended gripping system forcompressive testing CFCCs employs active grip interfaces thatrequire a continuous appli
41、cation of a mechanical, hydraulic, orpneumatic force to transmit the force applied by the testmachine to the test specimen. These types of grip interfaces(that is, frictional face-loaded grips) cause a force to be appliednormal to the surface of the gripped section of the testspecimen. Transmission
42、of the uniaxial force applied by thetest machine is then accomplished by friction between the testspecimen and the grip faces. Thus, important aspects of activegrip interfaces are uniform contact between the gripped sectionFIG. 1 Schematic Diagram of One Possible Apparatus forConducting a Uniaxially
43、-Loaded Compression TestC1358053of the test specimen and the grip faces and constant coefficientof friction over the grip/specimen interface.6.2.1.2 For flat test specimens, frictional face-loaded grips,either by direct lateral pressure grip faces (1)3or by indirectwedge-type grip faces, act as the
44、grip interface (2,3) asillustrated in Fig. 2 and Fig. 3, respectively. Generally, closetolerances are required for the flatness and parallelism as wellas for the wedge angle of the wedge grip faces. In addition, thethickness, flatness, and parallelism of the gripped section of thetest specimen must
45、be within similarly close tolerances topromote uniform contact at the test specimen/grip interface.Tolerances will vary depending on the exact configuration asshown in the appropriate test specimen drawings.6.2.1.3 Sufficient lateral pressure must be applied to preventslippage between the grip face
46、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. Keep the serra-tions clean and well-defined but not overly sharp. The lengthand width of the grip face
47、s shall be equal to or greater than therespective length and width of the gripped sections of the testspecimen.6.2.1.4 An alternative recommended gripping system forcompressive testing CFCCs employs passive grip interfaceswhich employ lateral supports and loading anvils to transmitthe applied force
48、to the compressive test specimen. The lateralsupports prevent both buckling of the test specimen in the gagesection and splitting and brooming of the 8grip section.Transmission of the force applied by the test machine is thenaccomplished by a directly applied uniaxial force to the testspecimen ends.
49、 Thus, important aspects of this type of gripinterface are uniform contact between the loading anvil and thetest specimen and good contact between the test specimen andlateral supports.6.2.1.5 For flat test specimens, a controlled, face-supportedfixture (4) as illustrated in Fig. 4 can be used. Generally, closetolerances are required for the flatness and parallelism. Inaddition, the thickness, flatness, and parallelism of the sup-ported section of the test specimen must be within similarlyclose tolerances to promote uniform contact at the tes
