1、Designation: C1323 10C1323 16Standard Test Method forUltimate Strength of Advanced Ceramics with DiametrallyCompressed C-Ring Specimens at Ambient Temperature1This standard is issued under the fixed designation C1323; the number immediately following the designation indicates the year oforiginal ado
2、ption 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. Scope*Scope1.1 This test method covers the determination of ultimate strength un
3、der monotonic loading of advanced ceramics in tubularform at ambient temperatures. The ultimate strength as used in this test method refers to the strength obtained under monotoniccompressive loading of C-ring specimens such as shown in Fig. 1 where monotonic refers to a continuous nonstop test rate
4、 withno reversals from test initiation to final fracture. This method permits a range of sizes and shapes since test specimens may beprepared from a variety of tubular structures. The method may be used with microminiature test specimens.1.2 The values stated in SI units are to be regarded as standa
5、rd. No other units of measurement are included in this standard.1.2.1 Values expressed in this test method are in accordance with the International System of Units (SI) and IEEE/ASTM SI10.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is
6、 the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C1145 Terminology of Advanced CeramicsC1161 Test Method for Flexural Strength of Advan
7、ced Ceramics at Ambient TemperatureC1239 Practice for Reporting Uniaxial Strength Data and Estimating Weibull Distribution Parameters for Advanced CeramicsC1322 Practice for Fractography and Characterization of Fracture Origins in Advanced CeramicsC1368 Test Method for Determination of Slow Crack Gr
8、owth Parameters of Advanced Ceramics by Constant Stress-RateStrength Testing at Ambient TemperatureC1683 Practice for Size Scaling of Tensile Strengths Using Weibull Statistics for Advanced CeramicsE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanica
9、l TestingE337 Test Method for Measuring Humidity with a Psychrometer (the Measurement of Wet- and Dry-Bulb Temperatures)IEEE/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 advanced ceramican enginee
10、red, high-performance, predominately nonmetallic, inorganic, ceramic material havingspecific functional qualities. (C1145)3.1.2 breaking loadforcethe loadforce at which fracture occurs. (E6)3.1.3 C-ringcircular test specimen geometry with the mid-section (slot) removed to allow bending displacement
11、(compressionor tension). (E6)3.1.4 flexural strengtha measure of the ultimate strength of a specified beam in bending.3.1.5 modulus of elasticitythe ratio of stress to corresponding strain below the proportional limit. (E6)1 This test method is under the jurisdiction of ASTM Committee C28 on Advance
12、d Ceramics and is the direct responsibility of Subcommittee C28.04 on Applications.Current edition approved Jan. 1, 2010Jan. 15, 2016. Published March 2010February 2016. Originally approved in 1996. Last previous edition approved in 20012010 asC1323 96 (2001)C1323 10.1. DOI: 10.1520/C1323-10.10.1520
13、/C1323-16.2 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.This document is not an ASTM standard and is intend
14、ed 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 adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current
15、 versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.6 slow crack growthsubcritical
16、 crack growth (extension) which may result from, but is not restricted to, such mechanismsas environmentally assisted stress corrosion or diffusive crack growth.4. Significance and Use4.1 This test method may be used for material development, material comparison, quality assurance, and characterizat
17、ion.Extreme care should be exercised when generating design data.4.2 For a C-ring under diametral compression, the maximum tensile stress occurs at the outer surface. Hence, the C-ringspecimen loaded in compression will predominately evaluate the strength distribution and flaw population(s) on the e
18、xternalsurface of a tubular component. Accordingly, the condition of the inner surface may be of lesser consequence in specimenpreparation and testing.NOTE 1A C-ring in tension or an O-ring in compression may be used to evaluate the internal surface.4.2.1 The flexure stress is computed based on simp
19、le curved-beam theory (1, 2, 3, 4, 5).3 It is assumed that the material isisotropic and homogeneous, the moduli of elasticity are identical in compression or tension, and the material is linearly elastic.These homogeneity and isotropy assumptions preclude the use of this standard for continuous fibe
20、r reinforced composites.Averagegrain size(s) should be no greater than one fiftieth (150) of the C-ring thickness.The simple curved-beam theory stress solution fromengineering mechanics is in good agreement (typically better than 1%) with a theory of (within 2 %) with an elasticity solutionas discus
21、sed in (36) for the test specimen geometries chosenrecommended for this standard. The simplecurved beam theory stressequations are relatively simple. They are relatively simple and straightforward, and therefore it is relatively easy to integrate forWeibull effective volume or effective area computa
22、tions as shownthe equations for calculations for effective area or effectivevolume for Weibull analyses as discussed in Appendix X1.4.2.2 The simple curved beam and theory of elasticity stress solutions both are two-dimensional plane stress solutions. They donot account for stresses in the axial (pa
23、rallel to b) direction, or variations in the circumferential (hoop, ) stresses through thewidth (b) of the test piece. The variations in the circumferential stresses increase with increases in width (b) and ring thickness(t). The variations can be substantial (10 %) for test specimens with large b.
24、The circumferential stresses peak at the outer edges.Therefore, the width (b) and thickness (t) of the specimens permitted in this test method are limited so that axial stresses arenegligible (see Ref. 5) and the variations of the circumferential stresses from the nominal simple curved beam theory s
25、tress3 The boldface numbers in parentheses refer to a list of references at the end of this test method.FIG. 1 C-Ring Test Geometry with Defining Geometry and Reference Angle () for the Point of Fracture Initiation on the CircumferenceC1323 162calculations are typically less than 4 %. See Ref. (34)
26、and (46) for more information on the variation of the circumferential stressesas a function of ring thickness (t) and ring width (b).4.2.3 The test piece outer rim corners are vulnerable to edge damage, another reason to minimize the differences in thecircumferential stresses across the ring outer s
27、urface.4.2.4 Other geometry Cring test specimens may be tested, but comprehensive finite element analyses shall be performed toobtain accurate stress distributions. If strengths are to be scaled (converted) to strengths of other sizes or geometries, then Weibulleffective volumes or areas shall be co
28、mputed using the results of the finite element analyses.4.3 Because advanced ceramics exhibiting brittle behavior generally fracture catastrophically from a single dominant flaw fora particular tensile stress field, field in quasi-static loading, the surface area and volume of material subjected to
29、tensile stressesis a significant factor in determining the ultimate strength. Moreover, because of the statistical distribution of the flaw population(s)in advanced ceramics exhibiting brittle behavior, a sufficient number of specimens at each testing condition is required forstatistical analysis an
30、d design. This test method provides guidelines for the number of specimens that should be tested for thesepurposes (see 8.4).4.4 Because of a multitude of factors related to materials processing and component fabrication, the results of C-ring tests froma particular material or selected portions of
31、a part, or both, may not necessarily represent the strength and deformation propertiesof the full-size end product or its in-service behavior.4.5 The ultimate strength of a ceramic material may be influenced by slow crack growth or stress corrosion, or both, and istherefore, sensitive to the testing
32、 mode, testing rate, or environmental influences, or a combination thereof. Testing at sufficientlyrapid rates as outlined in this test method may minimize the consequences of subcritical (slow) crack growth or stress corrosion.4.6 The flexural behavior and strength of an advanced monolithic ceramic
33、 are dependent on the materials inherent resistanceto fracture, the presence of flaws, or damage accumulation processes, or a combination thereof. Analysis of fracture surfaces andfractography, though beyond the scope of this test method, is highly recommended (further guidance may be obtained fromP
34、ractice C1322 and Ref (67).5. Interferences5.1 Test environment (vacuum, inert gas, ambient air, etc.) including moisture content (that is, relative humidity) may have aninfluence on the measured ultimate strength. In particular, the behavior of materials susceptible to slow crack-growth fracture wi
35、llbe strongly influenced by test environment and testing rate. Testing to evaluate the maximum inert strength (strength potential) ofa material shall therefore be conducted in inert environments or at sufficiently rapid testing rates, or both, so as to minimize slowcrack-growth effects. Conversely,
36、testing can be conducted in environments and testing modes and rates representative of serviceconditions to evaluate material performance under use conditions. When testing in uncontrolled ambient air for the purpose ofevaluating maximum inert strength (strength potential), relative humidity and tem
37、perature must be monitored and reported. Testingat humidity levels 65 % RH is not recommended and any deviations from this recommendation must be reported.5.2 C-ring specimens are useful for the determination of ultimate strength of the outer diameter of tubular components in theas-received/as-used
38、condition without surface preparations that may distort the strength controlling flaw population(s).Nonetheless, machining damage introduced during specimen preparation can be either a random interfering factor in thedetermination of the maximum inert strength (strength potential), or an inherent pa
39、rt of the strength characteristics being measured.Universal or standardized methods of surface/sample preparation do not exist. Hence, final machining steps may or may not negatemachining damage introduced during the initial machining. Thus, specimen fabrication history may play an important role in
40、 themeasured strength distributions and shall be reported.5.3 Very small C-ring test specimens made by micro fabrication methods may also be tested. These typically are tested in theas-fabricated state and do not require any machining preparation. Chamfers or edge bevels may not be necessary. Dimens
41、ionalnonuniformities (e.g., through-thickness tapers or fabrication template artifacts) may alter the stress state and create experimentalerrors.6. Apparatus6.1 LoadingSpecimens shall be loaded in any suitable testing machine provided that uniform rates of direct loading can bemaintained. The system
42、 used to monitor the loading shall be free from any initial lags and will have the capacity to record themaximum loadforce applied to the C-ring specimen during the test. Testing machine accuracy shall be within 1.0 % in accordancewith Practices E4.6.1.1 This test method permits the use of either fi
43、xed loading rams or, when necessary (see 9.3), a self-adjusting fixture. Aself-adjusting fixture may include a universal joint or spherically seated platen used in conjunction with the upper loading ram.Such an articulating fixture may be necessary to ensure even line loading from front to back acro
44、ss the top of a C-ring testspecimen. Articulation from side to side is not required since a flat loading platen contacts the C-ring at its top on its centerline.When fixed loading rams are used, they shall be aligned so that the platen surfaces which come into contact with the specimensC1323 163are
45、parallel to within 0.015 mm over the width of the test piece. Alignment of the testing system must be verified at a minimumat the beginning and at the end of a test series. An additional verification of alignment is recommended, although not required, atthe middle of the test series.NOTE 2Atest seri
46、es is interpreted to mean a discrete group of tests on individual specimens conducted within a discrete period of time on a particularmaterial configuration, test specimen geometry, test conditions, or other uniquely definable qualifier. For example, a test series may be composed of onematerial comp
47、rising ten specimens of one geometry tested at a fixed rate in strain control to final fracture in ambient air).6.1.2 Materials such as foil or thin rubber sheet shall be used between the loading rams and the specimen for ambienttemperature tests to reduce the effects of friction and to redistribute
48、 the load.force. Aluminum oxide (alumina) felt or otherhigh-temperature “cloth” with a high-temperature capability may also be used at ambient or elevated temperature. The use of amaterial with a high-temperature capability is recommended to ensure consistency with elevated temperature tests (if pla
49、nned),provided the high-temperature “cloth” is chemically compatible with the specimen at all testing temperatures.6.2 The fixture used during the tests shall be stiffer than the specimen to ensure that a majority of the crosshead travel (at least80 %) is imposed on the C-ring specimen.6.3 Data AcquisitionAt the minimum, an autographic record of applied loadforce shall be obtained. Either analog chartrecorders or digital data acquisition systems can be used for this purpose. Ideally, an analog chart recorder or plotter shall be usedin conjunction with a digi
