1、Designation: C 1469 00 (Reapproved 2005)Standard Test Method forShear Strength of Joints of Advanced Ceramics at AmbientTemperature1This standard is issued under the fixed designation C 1469; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, 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 covers the determination of shearstrength of joints in advanced ceramics at amb
3、ient temperature.Test specimen geometries, test specimen fabrication methods,testing modes (that is, force or displacement control), testingrates (that is, force or displacement rate), data collection, andreporting procedures are addressed.1.2 This test method is used to measure shear strength ofcer
4、amic joints in test specimens extracted from larger joinedpieces by machining. Test specimens fabricated in this way arenot expected to warp due to the relaxation of residual stressesbut are expected to be much straighter and more uniformdimensionally than butt-jointed test specimens prepared byjoin
5、ing two halves, which are not recommended. In addition,this test method is intended for joints, which have either low orintermediate strengths with respect to the substrate material tobe joined. Joints with high strengths should not be tested bythis test method because of the high probability of inv
6、alid testsresulting from fractures initiating at the reaction points ratherthan in the joint. Determination of the shear strength of jointsusing this test method is appropriate particularly for advancedceramic matrix composite materials but also may be useful formonolithic advanced ceramic materials
7、.1.3 Values expressed in this test method are in accordancewith the International System of Units (SI) and PracticeIEEE/ASTM SI 10.1.4 This test method does not purport to address the safetyproblems associated with its use. It is the responsibility of theuser of this test method to establish appropr
8、iate safety andhealth practices and determine the applicability of regulatorylimitations prior to use. Specific precautionary statements arenoted in 8.1 and 8.2.2. Referenced Documents2.1 ASTM Standards:2C 1145 Terminology of Advanced CeramicsC 1161 Test Method for Flexural Strength of AdvancedCeram
9、ics at Ambient TemperaturesC 1211 Test Method for Flexural Strength of AdvancedCeramics at Elevated TemperaturesC 1275 Test Method for Monotonic Tensile Behavior ofContinuous Fiber-Reinforced Advanced Ceramics withSolid Rectangular Cross-Section Test Specimens at Ambi-ent TemperatureC 1341 Test Meth
10、od for Flexural Properties of ContinuousFiber-Reinforced Advanced Ceramic CompositesD 3878 Terminology of High-Modulus Reinforcing Fibersand Their CompositesD 5379/D 5379M Test Method for Shear Properties ofComposite Materials by the V-Notched Beam MethodE4 Practices for Force Verification of Testin
11、g MachinesE6 Terminology Relating to Methods of Mechanical Test-ingE 122 Practice for Choice of Sample Size to Estimate theAverage Quality of a Lot ProcessE 337 Test Method for Measuring Humidity with Psy-chrometer (the Measurement of Wet-Bulb and Dry-BulbTemperatures)IEEE/ASTM SI 10 American Nation
12、al Standard for Use ofthe International System of Units (SI): The Modern MetricSystem3. Terminology3.1 DefinitionsThe definitions of terms relating to shearstrength testing appearing in Terminology E6, to advancedceramics appearing in Terminologies C 1145 and D 3878 applyto the terms used in this te
13、st method. Additional terms used inconjunction with this test method are defined as follows.3.1.1 advanced ceramic, nhighly-engineered, high-performance predominately nonmetallic, inorganic, ceramic1This test method is under the jurisdiction of ASTM Committee C28 onAdvanced Ceramics and is the direc
14、t responsibility of Subcommittee C28.07 onCeramic Matrix Composites.Current edition approved June 1, 2005. Published June 2005. Originallyapproved in 2000. Last previous edition approved in 2000 as C 1469 00.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Custome
15、r Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.material having specific functional at
16、tributes. C 11453.1.2 breaking force F, nforce at which fracture occurs.3.1.3 ceramic matrix composite, nmaterial consisting oftwo or more materials (insoluble in one another), in which themajor, continuous component (matrix component) is a ceramicwhile the secondary component(s) may be ceramic, gla
17、ss-ceramic, glass, metal, or organic in nature. These componentsare combined on macroscale to form a useful engineeringmaterial possessing certain properties or behavior not pos-sessed by the individual constituents. C 12753.1.4 joining, ncontrolled formation of chemical, or me-chanical bond, or bot
18、h, between similar or dissimilar materials.3.1.5 shear strength F/L2, nmaximum shear stresswhich a material is capable of sustaining. Shear strength iscalculated from the shear fracture force and the shear stressedarea.4. Summary of Test Method4.1 This test method describes an asymmetrical four-poin
19、tflexure test method to determine shear strengths of advancedceramic joints. Test specimens and test setup are shownschematically in Fig. 1 and Fig. 2, respectively. Selection of thetest specimen geometry depends on the bond strength of thejoint, which may be determined by preparing longer testNOTE
20、1The width of the joint, which varies between 0.05 and 0.20 mm, based on the joining method used, is smaller than that of the notch in b).All dimensions are given in mm.FIG. 1 Schematics of Test Specimen Geometries: a) Uniform, b) Straight-Notched and c) V-NotchedC 1469 00 (2005)2specimens of the sa
21、me cross-section and using a standardfour-point flexural strength test, for example, Test MethodC 1161 for monolithic advanced ceramic base material andTest Method C 1341 for composite advanced ceramic basematerial. If the joint flexural strength is low (that is, 50 % of theflexural strength of the
22、base material) this test method shouldnot be used to measure shear strength of advanced ceramicjoints because very high contact stresses at the reaction pointswill provide a high probability of invalid tests (that is, fracturesnot at the joint).4.2 The testing arrangement of this test method is asym
23、-metrical flexure, as illustrated by the force, shear and momentdiagrams in Fig. 3a, Fig. 3b, and Fig. 3c, respectively. Note thatthe greatest shear exists over a region of 6 Si/2 around thecenterline of the joint (see Fig. 3b). In addition, while themoment is zero at the centerline of the joint, th
24、e maximummoments occur at the inner reaction points (see Fig. 3c). Thepoints of maximum moments are where the greatest probabilityof fracture of the base material may occur if the joint flexuralstrength, and therefore, joint shear strength is too high.5. Significance and Use5.1 Advanced ceramics are
25、 candidate materials for struc-tural applications requiring high degrees of wear and corrosionresistance, often at elevated temperatures.5.2 Joints are produced to enhance the performance andapplicability of materials. While the joints between similarmaterials are generally made for manufacturing co
26、mplex partsand repairing components, those involving dissimilar materialsusually are produced to exploit the unique properties of eachFIG. 2 Schematic of Test FixtureFIG. 3 Idealized a) Force, b) Shear, and c) Moment Diagrams forAsymmetric Four-point Flexure, Where Soand SiAre the Outerand Inner Rea
27、ction Span Distances, Respectively, and P is theApplied ForceC 1469 00 (2005)3constituent in the new component. Depending on the joiningprocess, the joint region may be the weakest part of thecomponent. Since under mixed-mode and shear loading, theload transfer across the joint requires reasonable s
28、hear strength,it is important that the quality and integrity of joint underin-plane shear forces be quantified. Shear strength data are alsoneeded to monitor the development of new and improvedjoining techniques.5.3 Shear tests provide information on the strength anddeformation of materials under sh
29、ear stresses.5.4 This test method may be used for material development,material comparison, quality assurance, characterization, anddesign data generation.5.5 For quality control purposes, results derived from stan-dardized shear test specimens may be considered indicative ofthe response of the mate
30、rial from which they were taken forgiven primary processing conditions and post-processing heattreatments.6. Interferences6.1 Fractures that initiate outside of the joint region may bedue to factors, such as localized stress concentrations, extra-neous stresses introduced by improper force transfer.
31、 Suchfractures will constitute invalid tests.6.2 Since the joint width is typically small, that is, 0.05 to0.20 mm, the proper machining of the notches at the jointregion is very critical (see Fig. 1). Improper machining of thenotches can lead to undesired fracture at the reaction points.Furthermore
32、, nonsymmetrical machining of the nothces can bedecisive as to how the fracture occurs between the nothces.NOTE 1Finite element stress analysis of nonsymmetrical nothcesshowed that when there is a misalignment between the notches and themid-plane of the joint, spurious normal (sx) tensile stresses a
33、re generatedat the notches which tend to “tear” the joint and would artificially affect(reduce) the magnitude of shear strength measured from the joint. Themagnitude of these tensile stresses could be significant depending on thematerial system being investigated. Based on this analysis, it is recom
34、-mended that the ratio of misalignment between the notch root andmid-plane of the joint, d, and the distance between the notches, h, shouldbe kept to less than 0.0125. (See Fig. 4.)6.3 In this test method, the shear force required to causefracture in the joint region depends on the span lengths of S
35、oand Siin the fixture3(see Fig. 3). These lengths and the strengthof the joint relative to that of the base material determinewhether fracture takes place at the joint region or at thereaction points. Depending on this relative strength, it may benecessary to conduct preliminary tests to establish t
36、he appro-priate Soand Sidistances for the fixture to be used.46.4 The accuracy of insertion and alignment of the testspecimen with respect to the fixture is critical; therefore,preparations for testing should be done carefully to minimizethe bending moment at the joint, which strongly depends on the
37、inner and outer reaction spans, as seen in Fig. 3c. See details in10.4.6.5 Test environment (vacuum, inert gas, ambient air, etc.)including moisture content, for example, relative humidity,may have an influence on the measured shear strength. Con-versely, testing can be conducted in environments and
38、 testingmodes and rates representative of service conditions to evalu-ate material performance under those conditions. When testingis conducted in uncontrolled ambient air with the objective ofevaluating maximum strength potential, relative humidity andtemperature must be monitored and reported. Tes
39、ting at hu-midity levels 65 % RH is not recommended and any devia-tions from this recommendation shall be reported.7. Apparatus7.1 Testing MachinesThe testing machine shall be inconformance with Practices E4. The forces used in determin-ing shear strength shall be accurate within 61 % at any forcewi
40、thin the selected force range of the testing machine asdefined in Practices E4.7.2 Data AcquisitionAt a minimum, autographic recordsof applied force and cross-head displacement versus time shallbe obtained. Either analog chart recorders or digital dataacquisition systems may be used for this purpose
41、 although adigital record is recommended for ease of later data analysis.Ideally, an analog chart recorder or plotter should be used inconjunction with the digital data acquisition system to providean immediate record of the test as a supplement to the digitalrecord. Recording devices shall be accur
42、ate to 61 % of fullscale and shall have a minimum data acquisition rate of 10 Hzwith a response of 50 Hz deemed more than sufficient.7.3 Dimension-Measuring DevicesMicrometers and otherdevices used for measuring linear dimensions must be accurateand precise to at least 0.01 mm.3J.M. Slepetz, T.F. Za
43、gaeski, and R.F. Novello, “In-Plane Shear Test forComposite Materials”, AMMRC-TR-78-30, Army Materials and Mechanics Re-search Center, Watertown, MA, July 1978.4. nal, I.E. Anderson, and S.I. Maghsoodi, “ATest Method to Measure ShearStrength of Ceramic Joints at High Temperatures,” J. Am. Ceram. Soc
44、., 80, 1281(1997).NOTE 1It is recommended that d/h ratio in both notch types is lessthan 0.0125.FIG. 4 Schematic of Misalignment, d, between the Joint Line andNotch Root Shown for StraightNotched SpecimenC 1469 00 (2005)47.4 Combination SquareUsed to draw perpendicular linesto specimen axis at the l
45、ocations of inner loading points. Thetolerance must be within 0.5.7.5 Test FixtureThe test fixture consists of top and bottomsections, reaction-pins, and a force transfer ball, as shownschematically in Fig. 2. The bottom section is placed on astationary base, for example, a compression platen. The t
46、estspecimen is positioned between the top and bottom sections ofthe fixture. The force is transmitted from the test machine to thefixture by the force transfer ball; however, a pin also can beused in place of the force transfer ball. Table 1 containssymbols, nomenclature, and recommended dimensions
47、for thetest fixture (Fig. 2), where the tolerances for Soand Siafteralignment is 60.2 mm (see 10.4 for details). The tolerances forthe diameter of the force transfer ball and reaction-pin are 60.1mm and 60.01 mm, respectively.NOTE 2The reaction-pin diameter in this standard is 3 mm, unlike thatin Te
48、st Method C 1161 where it is a 4.5 mm. Unpublished finite elementanalyses have indicated that the smaller pin diameter better approximatesthe “point loading”, thus the stress profile at the joint in Fig. 3.NOTE 3It should be indicated that when there are restrictions for pinsto rotate freely, as in
49、Fig. 2, the resulting friction may become a factor inthe measurements, as indicated in Test Method C 1161. So far, however,no systematic study has been conducted in the current test methodregarding this issue.7.5.1 Test fixtures, including the pins and ball, and loadingrams shall be stiff and elastic under loading. These pieces maybe made of a ceramic with an elastic modulus between 200 and400 GPa and a flexural strength no less than 275 MPa, asspecified in Test Method C 1211. Dense high purity siliconcarbide and alumina are the typical candidate materials
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