1、Designation: C1341 06C1341 13Standard Test Method forFlexural Properties of Continuous Fiber-ReinforcedAdvanced Ceramic Composites1This standard is issued under the fixed designation C1341; the number immediately following the designation indicates the year oforiginal adoption or, in the case of rev
2、ision, 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 Scope*1.1 This test method covers the determination of flexural properties of continuous fiber-reinfor
3、ced ceramic composites in theform of rectangular bars formed directly or cut from sheets, plates, or molded shapes. Three test geometries are described asfollows:1.1.1 Test Geometry IA three-point loading system utilizing center point force application on a simply supported beam.1.1.2 Test Geometry
4、IIAA four-point loading system utilizing two force application points equally spaced from their adjacentsupport points with a distance between force application points of one half of the support span.1.1.3 Test Geometry IIBA four-point loading system utilizing two force application points equally sp
5、aced from their adjacentsupport points with a distance between force application points of one third of the support span.1.2 This test method applies primarily to all advanced ceramic matrix composites with continuous fiber reinforcement:uni-directional (1-D), bi-directional (2-D), tri-directional (
6、3-D), and other continuous fiber architectures. In addition, this testmethod may also be used with glass (amorphous) matrix composites with continuous fiber reinforcement. However, flexuralstrength cannot be determined for those materials that do not break or fail by tension or compression in the ou
7、ter fibers. This testmethod does not directly address discontinuous fiber-reinforced, whisker-reinforced, or particulate-reinforced ceramics. Thosetypes of ceramic matrix composites are better tested in flexure using Test Methods C1161 and C1211.1.3 Tests can be performed at ambient temperatures or
8、at elevated temperatures. At elevated temperatures, a suitable furnaceis necessary for heating and holding the test specimens at the desired testing temperatures.1.4 This test method includes the following:SectionScope 1Referenced Documents 2Terminology 3Summary of Test Method 4Significance and Use
9、5Interferences 6Apparatus 7Precautionary Statement 8Test specimens 9Procedures 10Calculation of Results 11Report 12Precision and Bias 13Keywords 14ReferencesCFCC Surface Condition andFinishingAnnex A1Conditions and Issues in HotLoading of Test specimensinto FurnacesAnnex A2Toe Compensation on Stress
10、-Strain CurvesAnnex A3Corrections for ThermalExpansion in FlexuralEquationsAnnex A41 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 MatrixComposites.Current edition approved Jan. 1, 2006Feb. 15,
11、 2013. Published January 2006April 2013. Originally approved in 1996. Last previous edition approved in 20052006 asC1341 00C1341 06. (2005). DOI: 10.1520/C1341-06.10.1520/C1341-13.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what
12、 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 versionof the standard as published by ASTM is to be considered the
13、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 States1Example of Test Report Appendix X11.5 The values stated in SI units are to be regarded as the standard
14、in accordance with IEEE/ASTM SI 10 .1.6 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 applicability of regulatorylimita
15、tions prior to use.2. Referenced Documents2.1 ASTM Standards:2C1145 Terminology of Advanced CeramicsC1161 Test Method for Flexural Strength of Advanced Ceramics at Ambient TemperatureC1211 Test Method for Flexural Strength of Advanced Ceramics at Elevated TemperaturesC1239 Practice for Reporting Uni
16、axial Strength Data and Estimating Weibull Distribution Parameters for Advanced CeramicsC1292 Test Method for Shear Strength of Continuous Fiber-Reinforced Advanced Ceramics at Ambient TemperaturesD790 Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insula
17、ting MaterialsD2344/D2344M Test Method for Short-Beam Strength of Polymer Matrix Composite Materials and Their LaminatesD3878 Terminology for Composite MaterialsD6856 Guide for Testing Fabric-Reinforced “Textile” Composite MaterialsE4 Practices for Force Verification of Testing MachinesE6 Terminolog
18、y Relating to Methods of Mechanical TestingE122 Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot orProcessE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE220 Test Method for Calibration of Thermocouples B
19、y Comparison TechniquesE337 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 Precision of a Test MethodIEEE/ASTM SI 10 American National Standard for Use of the Internation
20、al System of Units (SI): The Modern Metric System3. Terminology3.1 Definitions:3.1.1 The definitions of terms relating to flexure 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 appl
21、y to the terms used in this test method.The definitions of terms relating to fiber-reinforced composites appearing in Terminology D3878 apply to the terms used in thistest method. Pertinent definitions as listed in Test Method C1161, Test Methods D790, Terminology C1145, Terminology D3878,andTermino
22、logy E6 are shown in the following with the appropriate source given in brackets.Additional terms used in conjunctionwith this test method are also defined in the following.3.1.2 advanced ceramic, nhighly engineered, high-performance, predominately nonmetallic, inorganic, ceramic materialhaving spec
23、ific functional attributes. C11453.1.3 breaking force, n FThe force at which fracture occurs. (In this test method, fracture consists of breakage of the testbar into two or more pieces or a loss of at least 20 % of the maximum force carrying capacity.) E63.1.4 ceramic matrix composite, nmaterial con
24、sisting 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) (reinforcing component) may beceramic, glass-ceramic, glass, metal, or organic in nature. These components are combined on a macroscal
25、e to form a usefulengineering material possessing certain properties or behavior not possessed by the individual constituents.3.1.5 continuous fiber-reinforced ceramic composite (CFCC), nceramic matrix composite in which the reinforcing phaseconsists of a continuous fiber, continuous yarn, or a wove
26、n fabric.3.1.6 flexural strength, n FL2measure of the ultimate strength of a specified beam in bending. C11613.1.7 four-point-13 point flexure, na configuration of flexural strength testing where a test specimen is symmetrically loadedat two locations that are situated one third of the overall span
27、away from the outer two support bearings.3.1.8 four-point-14 point flexure, na configuration of flexural strength testing where a test specimen is symmetrically loadedat two locations that are situated one quarter of the overall span away from the outer two support bearings. C11613.1.9 fracture stre
28、ngth, n FL2the calculated flexural stress at the breaking force.3.1.10 modulus of elasticity, n FL2the ratio of stress to corresponding strain below the proportional limit. E62 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For
29、Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.C1341 1323.1.11 proportional limit stress, n FL2greatest stress that a material is capable of sustaining without any deviation fromproportionality of stress to strain (Hookes law).3.1.11
30、.1 DiscussionMany experiments have shown that values observed for the proportional limit vary greatly with the sensitivity and accuracy of thetesting equipment, eccentricity of force application, the scale to which the stress-strain diagram is plotted, and other factors. Whendetermination of proport
31、ional limit is required, the procedure and sensitivity of the test equipment shall be specified. E63.1.12 slow crack growth, nsubcritical crack growth (extension) that may result from, but is not restricted to, suchmechanisms as environmentally assisted stress corrosion or diffusive crack growth.3.1
32、.13 span-to-depth ratio, n ndfor a particular test specimen geometry and flexure test configuration, the ratio (L/d) of theouter support span length (L) of the flexure test specimen to the thickness/depth (d) of test specimen (as used and described in TestMethod D790).3.1.14 three-point flexure, na
33、configuration of flexural strength testing where a test specimen is loaded at a location midwaybetween two support bearings. C11614. Summary of Test Method4.1 A bar of rectangular cross section is tested in flexure as a beam as in one of the following three geometries:4.1.1 Test Geometry IThe bar re
34、sts on two supports and force is applied by means of a loading roller midway between thesupports (see Fig. 1.)4.1.2 Test Geometry IIAThe bar rests on two supports and force is applied at two points (by means of two inner rollers), eachan equal distance from the adjacent outer support point. The inne
35、r support points are situated one quarter of the overall span awayfrom the outer two support bearings. The distance between the inner rollers (that is, the load span) is one half of the support span(see Fig. 1).4.1.3 Test Geometry IIBThe bar rests on two supports and force is applied at two points (
36、by means of two loading rollers),situated one third of the overall span away from the outer two support bearings. The distance between the inner rollers (that is,the inner support span) is one third of the outer support span (see Fig. 1).FIG. 1 FlexuralFlexure Test Geometries and Force DiagramC1341
37、1334.2 The test specimen is deflected until rupture occurs in the outer fibers or until there is a 20 % decrease from the peak force.4.3 The flexural properties of the test specimen (flexural strength and strain, fracture strength and strain, modulus of elasticity,and stress-strain curves) are calcu
38、lated from the force and deflection using elastic beam equations.5. Significance and Use5.1 This test method is used for material development, quality control, and material flexural specifications. Although flexuraltest methods are commonly used to determine design strengths of monolithic advanced c
39、eramics, the use of flexure test data fordetermining tensile or compressive properties of CFCC materials is strongly discouraged. The nonuniform stress distributions inthe flexure test specimen, the dissimilar mechanical behavior in tension and compression for CFCCs, low shear strengths ofCFCCs, and
40、 anisotropy in fiber architecture all lead to ambiguity in using flexure results for CFCC material design data (1-4).Rather, uniaxial-forced tensile and compressive tests are recommended for developing CFCC material design data based on auniformly stressed test condition.5.2 In this test method, the
41、 flexure stress is computed from elastic beam theory with the simplifying assumptions that thematerial is homogeneous and linearly elastic. This is valid for composites where the principal fiber direction is coincident/transverse with the axis of the beam. These assumptions are necessary to calculat
42、e a flexural strength value, but limit theapplication to comparative type testing such as used for material development, quality control, and flexure specifications. Suchcomparative testing requires consistent and standardized test conditions, that is, test specimen geometry/thickness, strain rates,
43、 andatmospheric/test conditions.5.3 Unlike monolithic advanced ceramics which fracture catastrophically from a single dominant flaw, CFCCs generallyexperience “graceful” fracture from a cumulative damage process. Therefore, the volume of material subjected to a uniformflexural stress may not be as s
44、ignificant a factor in determining the flexural strength of CFCCs. However, the need to test astatistically significant number of flexure test specimens is not eliminated. Because of the probabilistic nature of the strength ofthe brittle matrices and of the ceramic fiber in CFCCs, a sufficient numbe
45、r of test specimens at each testing condition is requiredfor statistical analysis, with guidelines for sufficient numbers provided in 9.7. Studies to determine the exact influence of testspecimen volume on strength distributions for CFCCs are not currently available.5.4 The four-point loading geomet
46、ries (Geometries IIAand IIB) are preferred over the three-point loading geometry (GeometryI). In the four-point loading geometry, a larger portion of the test specimen is subjected to the maximum tensile and compressivestresses, as compared to the three-point loading geometry. If there is a statisti
47、cal/Weibull character failure in the particularcomposite system being tested, the size of the maximum stress region will play a role in determining the mechanical properties.The four-point geometry may then produce more reliable statistical data.5.5 Flexure tests provide information on the strength
48、and deformation of materials under complex flexural stress conditions. InCFCCs nonlinear stress-strain behavior may develop as the result of cumulative damage processes (for example, matrix cracking,matrix/fiber debonding, fiber fracture, delamination, etc.) which may be influenced by testing mode,
49、testing rate, processing effects,or environmental influences. Some of these effects may be consequences of stress corrosion or subcritical (slow) crack growthwhich can be minimized by testing at sufficiently rapid rates as outlined in 10.3 of this test method.5.6 Because of geometry effects, the results of flexure tests of test specimens fabricated to standardized test dimensions froma particular material or selected portions of a component, or both, cannot be categorically used to define the strength anddeformation properties of the en
