【astm標(biāo)準(zhǔn)】c 1424 - 15

1、Designation: C1424 ? 15Standard Test Method for Monotonic Compressive Strength of Advanced Ceramics at Ambient Temperature1This standard is issued under the fixed designation C1424; the number immediately following the d

2、esignation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (´) indicates an editor

3、ial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of compres- sive strength including stress-strain behavior, under monotonic uniaxial loading of advanced ceramics at

4、ambient temperature. This test method is restricted to specific test specimen geom- etries. In addition, test specimen fabrication methods, testing modes (force or displacement), testing rates (force rate, stress rate, d

5、isplacement rate, or strain rate), allowable bending, and data collection and reporting procedures are addressed. Com- pressive strength as used in this test method refers to the compressive strength obtained under monot

6、onic uniaxial load- ing. Monotonic loading refers to a test conducted at a constant rate in a continuous fashion, with no reversals from test initiation to final fracture.1.2 This test method is intended primarily for us

7、e with advanced ceramics that macroscopically exhibit isotropic, homogeneous, continuous behavior. While this test method is intended for use on monolithic advanced ceramics, certain whisker- or particle-reinforced compo

8、site ceramics as well as certain discontinuous fiber-reinforced composite ceramics may also meet these macroscopic behavior assumptions. Generally, continuous fiber ceramic composites (CFCCs) do not macro- scopically exh

9、ibit isotropic, homogeneous, continuous behav- ior and, application of this test method to these materials is not recommended.1.3 Values expressed in this test method are in accordance with the International System of Un

10、its (SI) and IEEE/ASTM SI 10.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate saf

11、ety and health practices and determine the applica- bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C773 Test Method for Compressive (Crushing) Strength of Fired Whiteware Materia

12、lsC1145 Terminology of Advanced Ceramics D695 Test Method for Compressive Properties of Rigid PlasticsE4 Practices for Force Verification of Testing Machines E6 Terminology Relating to Methods of Mechanical Testing E83 P

13、ractice for Verification and Classification of Exten- someter SystemsE337 Test Method for Measuring Humidity with a Psy- chrometer (the Measurement of Wet- and Dry-Bulb Tem- peratures)E1012 Practice for Verification of T

14、esting Frame and Speci- men Alignment Under Tensile and Compressive Axial Force ApplicationIEEE/ASTM SI 10 Standard for Use of the International System of Units (SI) (The Modern Metric System3. Terminology3.1 Definitions

15、: 3.1.1 The definitions of terms relating to compressive test- ing appearing in Terminology E6, Test Method D695, and Terminology C1145 may apply to the terms used in this test method. Pertinent definitions as listed in

16、Practice E1012, Terminology C1145, and Terminology E6 are shown in the following with the appropriate source given in parentheses. Additional terms used in conjunction with this test method are defined in the following.

17、3.1.2 advanced ceramic, n—a highly engineered, high- performance predominately nonmetallic, inorganic, ceramic material having specific functional attributes. (C1145)3.1.3 axial strain, n [L/L]—the average longitudinal s

18、trains measured at the surface on opposite sides of the longitudinal axis of symmetry of the specimen by two strain-sensing devices located at the mid length of the reduced section. (E1012) 1 This test method is under th

19、e jurisdiction of ASTM Committee C28 on Advanced Ceramics and is the direct responsibility of Subcommittee C28.01 on Mechanical Properties and Performance. Current edition approved July 1, 2015. Published October 2015. O

20、riginally published in 1999. Last previous edition approved in 2015 as C1424 – 10 (2015). DOI: 10.1520/C1424-15.2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at s

21、ervice@astm.org. For Annual Book of ASTM Standards volume information, refer to the standard’s Document Summary page on the ASTM website.Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Consh

22、ohocken, PA 19428-2959. United States1advanced ceramics, test specimen fabrication history may play an important role in the measured compressive strength distri- butions and should be reported. In addition, the nature o

23、f fabrication used for certain advanced ceramics (for example, pressureless sintering, hot pressing) may require the testing of test specimens with gage sections in the as-processed condition (that is, it may not be poss

24、ible or desired/required to machine some test specimen surfaces not directly in contact with test fixture components). For very rough or wavy as-processed surfaces eccentricities in the stress state due to nonsymmetric c

25、ross sections as well as variation in the cross-sectional dimensions may also interfere with the compressive strength measurement. Finally, close geometric tolerances, particularly in regard to flatness, concentricity, a

26、nd cylindricity of test specimen surfaces or geometric entities in contact with the test fixture components) are critical requirements for successful compression tests.5.3 Bending in uniaxial compression tests can introd

27、uce eccentricity leading to geometric instability of the test speci- men and buckling failure before valid compressive strength is attained. In addition, if deformations or strains are measured at surfaces where maximum

28、or minimum stresses occur, bending may introduce over or under measurement of strains depending on the location of the strain-measuring device on the test specimen.5.4 Fractures that initiate outside the uniformly stress

29、ed gage section or splitting of the test specimen along its longitudinal centerline may be due to factors such as stress concentrations or geometrical transitions, extraneous stresses introduced by the load fixtures, mis

30、alignment of the test specimen/loading blocks, nonflat loading blocks or nonflat test specimen ends, or both, or strength-limiting features in the microstructure of the test specimen. Such non-gage section fractures will

31、 normally constitute invalid tests.6. Apparatus6.1 Testing Machines—Machines used for compression test- ing shall conform to the requirements of Practices E4. The forces used in determining compressive strength shall be

32、accurate within 61 % at any force within the selected force range of the testing machine as defined in Practices E4. A schematic showing pertinent features of one possible compres- sive testing apparatus is shown in Fig.

33、 1. Check that the expected breaking force for the desired test specimen geometry and test material is within the capacity of the test machine and force transducer. Advanced ceramic compression test speci- mens require m

34、uch greater forces to fracture than those usually encountered in tension or flexure test specimens of the same material.6.2 Loading Fixtures: 6.2.1 General—Compression loading fixtures are generally composed of two parts

35、: (1) basic steel compression fixtures (for example, platens) attached to the test machine and (2) loading blocks which are non-fixed and act as the interface between the compression platens and the test specimen. An ass

36、embly drawing of such a fixture and a test specimen is shown in Fig. 2. The brittle nature of advanced ceramics requires a uniforminterface between the loading fixtures and the test specimen. Line or point contact stress

37、es lead to crack initiation and fracture of the test specimen at stresses less than the actual compressive strength (that is, where actual strength is the intrinsic strength of the material not influenced by the test or

38、test conditions). In addition, large mismatches of Poisson’s ratios or elastic moduli between the loading fixture and test specimen, or both, can introduce lateral tensile forces leading to splitting of the compression t

39、est specimen. Similarly, plastic deformation of the load fixture can induce lateral tensile forces with the same effect. 6.2.1.1 Hardened (>48 HRc) steel compression platens shall be greater in diameter (≥25.4 mm) tha

40、n the loading blocks and shall be at least 25.4 mm in thickness. The loading surfaces of the compression platens shall be flat to 0.005 mm. In addition, the two loading surfaces (loading face used to contact the loading

41、blocks and bolted face used to attach the platen to the test machine) shall be parallel to 0.005 mm. When installed in the test machine, the loading surfaces of the upper and lower compression platens shall be parallel t

42、o each other within 0.01 mm and perpendicular to the load line of the test machine to within 0.01 mm (2). The upper and lower compression platens shall be concentric within 0.005 mm of each other and the load line of the

43、 test machine. Angular and concentricity alignments have been achieved with commercial alignment devices or by using available hole tolerances in commercial compression platens in conjunction with shims (2).FIG. 2 Exampl