ASTM C1273-2015 Standard Test Method for Tensile Strength of Monolithic Advanced Ceramics at Ambient Temperatures《在环境温度下测定整体高级陶瓷抗拉强度的标准试验方法》.pdf

1、Designation: C1273 05 (Reapproved 2010)C1273 15Standard Test Method forTensile Strength of Monolithic Advanced Ceramics atAmbient Temperatures1This standard is issued under the fixed designation C1273; the number immediately following the designation indicates the year oforiginal adoption or, in the

2、 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 determination of tensile strength under uniaxial loading of

3、 monolithic advanced ceramics atambient temperatures. This test method addresses, but is not restricted to, various suggested test specimen geometries as listed inthe appendix. In addition, test specimen fabrication methods, testing modes (force, displacement, or strain control), testing rates(force

4、 rate, stress rate, displacement rate, or strain rate), allowable bending, and data collection and reporting procedures areaddressed. Note that tensile strength as used in this test method refers to the tensile strength obtained under uniaxial loading.1.2 This test method applies primarily to advanc

5、ed ceramics that macroscopically exhibit isotropic, homogeneous, continuousbehavior. While this test method applies primarily to monolithic advanced ceramics, certain whisker- or particle-reinforcedcomposite ceramics as well as certain discontinuous fiber-reinforced composite ceramics may also meet

6、these macroscopicbehavior assumptions. Generally, continuous fiber ceramic composites (CFCCs) do not macroscopically exhibit isotropic,homogeneous, continuous behavior and application of this practice to these materials is not recommended.1.3 Values expressed in this test method are in accordance wi

7、th the International System of Units (SI) and SI10-02 IEEE/ASTMSI 10 .1.4 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 establish appropriate safety and health practices and determine the

8、 applicability of regulatorylimitations prior to use. Specific precautionary statements are given in Section 7.2. Referenced Documents2.1 ASTM Standards:2C1145 Terminology of Advanced CeramicsC1161 Test Method for Flexural Strength of Advanced Ceramics at Ambient TemperatureC1239 Practice for Report

9、ing Uniaxial Strength Data and Estimating Weibull Distribution Parameters for Advanced CeramicsC1322 Practice for Fractography and Characterization of Fracture Origins in Advanced CeramicsD3379 Test Method for Tensile Strength and Youngs Modulus for High-Modulus Single-Filament MaterialsE4 Practices

10、 for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE83 Practice for Verification and Classification of Extensometer SystemsE337 Test Method for Measuring Humidity with a Psychrometer (the Measurement of Wet- and Dry-Bulb Temperatures)E1012 Practice for

11、 Verification of Testing Frame and Specimen Alignment Under Tensile and Compressive Axial ForceApplicationSI10-02 IEEE/ASTM SI 10 American National Standard for Use of the International System of Units (SI): The Modern MetricSystem3. Terminology3.1 Definitions:1 This test method is under the jurisdi

12、ction of ASTM Committee C28 on Advanced Ceramics and is the direct responsibility of Subcommittee C28.01 on MechanicalProperties and Performance.Current edition approved June 1, 2010July 1, 2015. Published December 2010September 2015. Originally approved in 1994. Last previous edition approved in 20

13、052010as C1273 05.C1273 05 (2010). DOI: 10.1520/C1273-05R10.10.1520/C1273-15.2 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 t

14、he 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 changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users c

15、onsult 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, PA 19428-2959. United States13.1.1 The definitions of terms r

16、elating to tensile testing appearing in Terminology E6 apply to the terms used in this test methodon tensile testing. The definitions of terms relating to advanced ceramics testing appearing in Terminology C1145 apply to theterms used in this test method. Pertinent definitions as listed in Practice

17、C1239, Practice E1012, Terminology C1145, andTerminology E6 are shown in the following with the appropriate source given in parentheses.Additional terms used in conjunctionwith this test method are defined in the following:3.1.2 advanced ceramica highly engineered, high performance predominately non

18、metallic, inorganic, ceramic material havingspecific functional attributes. C11453.1.3 axial strainthe average of longitudinal strains measured at the surface on opposite sides of the longitudinal axis ofsymmetry of the specimen by two strain-sensing devices located at the mid length of the reduced

19、section. E10123.1.4 bending strainthe difference between the strain at the surface and the axial strain. In general, the bending strain variesfrom point to point around and along the reduced section of the specimen. E10123.1.5 breaking forcethe force at which fracture occurs. E63.1.6 fractographymea

20、ns and methods for characterizing a fractured specimen or component. C11453.1.7 fracture originthe source from which brittle fracture commences. C11453.1.8 percent bendingthe bending strain times 100 divided by the axial strain. E10123.1.9 slow crack growth (SCG)subcritical crack growth (extension)

21、which may result from, but is not restricted to, suchmechanisms as environmentally-assisted stress corrosion or diffusive crack growth. C11453.1.10 tensile strength,Suthe maximum tensile stress which a material is capable of sustaining.Tensile strength is calculatedfrom the maximum force during a te

22、nsion 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.4.2 High strength, monolithic advanced ceramic

23、materials generally characterized by small grain sizes (65 %relative humidity (RH) is not recommended and any deviations from this recommendation must be reported.5.2 Surface preparation of test specimens can introduce fabrication flaws that may have pronounced effects on tensile strength.Machining

24、damage introduced during test specimen preparation can be either a random interfering factor in the determination ofultimate strength of pristine material (that is, increase frequency of surface initiated fractures compared to volume initiatedfractures), or an inherent part of the strength character

25、istics to be measured. Surface preparation can also lead to the introductionof residual stresses. Universal or standardized test methods of surface preparation do not exist. It should be understood that finalmachining steps may or may not negate machining damage introduced during the early coarse or

26、 intermediate machining. Thus,test specimen fabrication history may play an important role in the measured strength distributions and should be reported.5.3 Bending in uniaxial tensile tests can cause or promote non-uniform stress distributions with maximum stresses occurringat the test specimen sur

27、face leading to non-representative fractures originating at surfaces or near geometrical transitions. Inaddition, if strains or deformations are measured at surfaces where maximum or minimum stresses occur, bending may introduceover or under measurement of strains. Similarly, fracture from surface f

28、laws may be accentuated or muted by the presence of thenon-uniform stresses caused by bending.6. Apparatus6.1 Testing MachinesMachines used for tensile testing shall conform to the requirements of Practices E4. The forces used indetermining tensile strength shall be accurate within 61 % at any force

29、 within the selected force range of the testing machine asdefined in Practices 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 measured force applied by the

30、testing machineto the test specimens. The brittle nature of advanced ceramics requires a uniform interface between the grip components and thegripped section of the test specimen. Line or point contacts and non-uniform pressure can produce Hertizan-type stresses leadingto crack initiation and fractu

31、re 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.FIG. 1 Schematic Diagram of One Possible Apparatus for Conducting a Uniaxially-Loaded Tensile TestC127

32、3 1536.2.2 Active Grip InterfacesActive grip interfaces require a continuous application of a mechanical, hydraulic, or pneumaticforce to transmit the force 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

33、 the gripped section of the test specimen. Transmission of the uniaxial force applied by thetest machine 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 specime

34、n and the grip faces and constant coefficient offriction over the grip/specimen interface.6.2.2.1 For cylindrical test specimens, a one-piece split-collet arrangement acts as the grip interface (1, 2)3 as illustrated in Fig.2. Generally, close tolerances are required for concentricity of both the gr

35、ip and test specimen diameters. In addition, the diameterof the gripped section of the test specimen and the unclamped, open diameter of the grip faces must be within similarly closetolerances to promote uniform contact at the test specimen/grip interface. Tolerances will vary depending on the exact

36、configuration as shown in the appropriate test specimen drawings.6.2.2.2 For flat test specimens, flat-face, wedge-grip faces act as the grip interface as illustrated in Fig. 3. Generally, closetolerances are required for the flatness and parallelism as well as wedge angle of the grip faces. In addi

37、tion, the thickness, flatness,and parallelism of the gripped section of the test specimen must be within similarly close tolerances to promote uniform contactat the test specimen/grip interface. Tolerances will vary depending on the exact configuration as shown in the appropriate testspecimen drawin

38、gs.6.2.3 Passive Grip InterfacesPassive grip interfaces transmit the force applied by the test machine to the test specimenthrough a direct mechanical link. Generally, these mechanical links transmit the test forces to the test specimen via geometricalfeatures of the test specimens such as button-he

39、ad fillets, shank shoulders, or holes in the gripped head. Thus, the important aspectof passive grip interfaces is uniform contact between the gripped section of the test specimen and the grip faces.3 The boldface numbers given in parentheses refer to a list of references at the end of the text.FIG.

40、 2 Example of a Smooth, Split Collet Active Gripping System for Cylindrical Test SpecimensFIG. 3 Example of a Smooth, Wedge Active Gripping System for Flat Test SpecimensC1273 1546.2.3.1 For cylindrical test specimens, a multi-piece split collet arrangement acts as the grip interface at button-head

41、fillets ofthe test specimen (3) as illustrated in Fig. 4. Because of the limited contact area at the test specimen/grip interface, soft, deformablecollet materials may be used to conform to the exact geometry of the test specimen. In some cases tapered collets may be usedto transfer the axial force

42、into the shank of the test specimen rather than into the button-head radius (3). Moderately close tolerancesare required for concentricity of both the grip and test specimen diameters. In addition, tolerances on the collet height must bemaintained to promote uniform axial-loading at the test specime

43、n/grip interface. Tolerances will vary depending on the exactconfiguration as shown in the appropriate test specimen drawings.6.2.3.2 For flat test specimens, pins or pivots act as grip interfaces at either the shoulders of the test specimen shank or at holesin the gripped test specimen head (4, 5,

44、6). Close tolerances are required of shoulder radii and grip interfaces to promote uniformcontact along the entire test specimen/grip interface as well as to provide for non-eccentric loading as shown in Fig. 5. Moderatelyclose tolerances are required for longitudinal coincidence of the pin and hole

45、 centerlines as illustrated in Fig. 6.6.3 Load Train Couplers:6.3.1 GeneralVarious types of devices (load train couplers) may be used to attach the active or passive grip interfaceassemblies to the testing machine. The load train couplers in conjunction with the type of gripping device play major ro

46、les in thealignment of the load train and thus subsequent bending imposed in the test specimen. Load train couplers can be classified as fixedand nonfixed as discussed in the following sections. Note that use of well-aligned fixed or self-aligning non fixed couplers doesnot automatically guarantee l

47、ow bending in the gage section of the tensile test specimen. Well-aligned fixed or self-aligning nonfixed couplers provide for well aligned load trains, but the type and operation of grip interfaces as well as the as-fabricateddimensions of the tensile test specimen can add significantly to the fina

48、l bending imposed in the gage section of the test specimen.6.3.1.1 Regardless of which type of coupler is used, alignment of the testing system must be verified as a minimum at thebeginning and end of a test series. An additional verification of alignment is recommended, although not required, at th

49、e middleof the test series. Either a dummy or actual test specimen and the alignment verification procedures detailed in the appendix mustbe used. Allowable bending requirements are discussed in 6.4. Tensile test specimens used for alignment verification should beequipped with a recommended eight separate longitudinal strain gages to determine bending contributions from both eccentric andangular misalignment of the grip heads. (Although it is possible to use a minimum of six separate longitudinal strain gages for testspecimens with circular cross sections, eigh