1、Designation: C1469 10 (Reapproved 2015)Standard Test Method forShear Strength of Joints of Advanced Ceramics at AmbientTemperature1This standard is issued under the fixed designation C1469; 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. Scope1.1 This test method covers the determination of shearstrength of joints in advanced ceramics at ambien
3、t 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 ofcerami
4、c 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 byjoining
5、 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 invali
6、d 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.1.
7、3 Values expressed in this test method are in accordancewith the International System of Units (SI) and IEEE/ASTM SI10 .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 appropriate safety
8、 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:2C1145 Terminology of Advanced CeramicsC1161 Test Method for Flexural Strength of AdvancedCeramics at Ambien
9、t TemperatureC1211 Test Method for Flexural Strength of AdvancedCeramics at Elevated TemperaturesC1275 Test Method for Monotonic Tensile Behavior ofContinuous Fiber-Reinforced Advanced Ceramics withSolid Rectangular Cross-Section Test Specimens at Am-bient TemperatureC1341 Test Method for Flexural P
10、roperties of ContinuousFiber-Reinforced Advanced Ceramic CompositesD3878 Terminology for Composite MaterialsD5379/D5379M Test Method for Shear Properties of Com-posite Materials by the V-Notched Beam MethodE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of M
11、echanical TestingE122 Practice for Calculating Sample Size to Estimate, WithSpecified Precision, the Average for a Characteristic of aLot or ProcessE337 Test Method for Measuring Humidity with a Psy-chrometer (the Measurement of Wet- and Dry-Bulb Tem-peratures)IEEE/ASTM SI 10 American National Stand
12、ard for Use ofthe International System of Units (SI): The Modern MetricSystem3. Terminology3.1 Definitions:3.1.1 The definitions of terms relating to shear strengthtesting appearing in Terminology E6, to advanced ceramicsappearing in Terminologies C1145 and D3878 apply to theterms used in this test
13、method. Additional terms used inconjunction with this test method are defined as follows.1This test method is under the jurisdiction of ASTM Committee C28 onAdvanced Ceramics and is the direct responsibility of Subcommittee C28.07 onCeramic Matrix Composites.Current edition approved Jan. 1, 2015. Pu
14、blished April 2015. Originallyapproved in 2000. Last previous edition approved in 2010 as C1469 10. DOI:10.1520/C1469-10R15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, r
15、efer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.2 advanced ceramic, nhighly-engineered, high-performance predominately nonmetallic, inorganic, ceramicmaterial having s
16、pecific functional attributes. C11453.1.3 breaking force F, nforce at which fracture occurs.3.1.4 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)
17、 may be ceramic, glass-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. C12753.1.5 joining, ncontrolled formation of chemical, or me-ch
18、anical bond, or both, between similar or dissimilar materials.3.1.6 shear strength F/L2, nmaximum shear stress that amaterial is capable of sustaining. Shear strength is calculatedfrom breaking force in shear and shear area.4. Summary of Test Method4.1 This test method describes an asymmetrical four
19、-pointflexure 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 test
20、specimens of the same cross-section and using a standardfour-point flexural strength test, for example, Test MethodC1161 for monolithic advanced ceramic base material and TestMethod C1341 for composite advanced ceramic base material.NOTE 1The width of the joint, which varies between 0.05 and 0.20 mm
21、, 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-NotchedC1469 10 (2015)2If the joint flexural strength is low (that is, 50 % of theflexural strength of th
22、e 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 as
23、ym-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,
24、the 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 a
25、re 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
26、complex partsand repairing components, those involving dissimilar materials usually 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
27、Reaction Span Distances, Respectively, and P is theApplied ForceC1469 10 (2015)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
28、 shear 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
29、shear 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 ma
30、terial 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 transfe
31、r. 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.Furthermo
32、re, nonsymmetrical machining of the nothces can bedecisive as to how the fracture occurs between the notches.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 (x) tensile stresses
33、are 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 reco
34、m-mended that the ratio of misalignment between the notch root andmid-plane of the joint, , 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.Conversely, testing can be conducted in environments andte
38、sting modes and rates representative of service conditions toevaluate material performance under those conditions. Whentesting is conducted in uncontrolled ambient air with theobjective of evaluating maximum strength potential, relativehumidity and temperature must be monitored and reported.Testing
39、at humidity levels 65 % RH is not recommended andany deviations from this recommendation shall be reported.7. Apparatus7.1 Testing MachinesThe testing machine shall be inconformance with Practices E4. The forces used in determiningshear strength shall be accurate within 61 % at any forcewithin the s
40、elected 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 although
41、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 accurate to 61
42、% 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. Zagaeski, an
43、d 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., 80, 128
44、1(1997).NOTE 1It is recommended that /h ratio in both notch types is lessthan 0.0125.FIG. 4 Schematic of Misalignment, , between the Joint Line andNotch Root Shown for StraightNotched SpecimenC1469 10 (2015)47.4 Combination SquareUsed to draw perpendicular linesto specimen axis at the locations of i
45、nner 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 testspecimen i
46、s 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 for thetest f
47、ixture (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 Test Method C11
48、61 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 Fig. 2, the re
49、sulting friction may become a factor inthe measurements, as indicated in Test Method C1161. So far, however, nosystematic study has been conducted in the current test method regardingthis 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 C1211. Dense high purity siliconcarbide and alumina are the typical candidate materials.Alternative
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