iTeh StandardsiTeh Standards
EURUSD
Your shopping cart is empty.
ASTM

ASTM C1421-01b

(Test Method)

Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperature

Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperature

SCOPE
1.1 These test methods cover the fracture toughness determination of KIpb (precracked beam specimen), KIsc (surface crack in flexure), and KIvb (chevron-notched beam specimen) of advanced ceramics at ambient temperature. The fracture toughness values are determined using beam test specimens with a sharp crack. The crack is either a straight-through crack (pb), or a semi-elliptical surface crack (sc), or it is propagated in a chevron notch (vb).
Note 1—The terms bend(ing) and flexure are synonymous in these test methods.
1.2 These test methods determine fracture toughness values based on a force and crack length measurement (pb,sc), or a force measurement and an inferred crack length (vb). In general, the fracture toughness is determined from maximum force. Applied force and displacement or an alternative (for example, time) are recorded for the pb specimen and vb specimen.
1.3 These test methods are applicable to materials with either flat or with rising R-curves. The fracture toughness measured from stable crack extension may be different than that measured from unstable crack extension. This difference may be more pronounced for materials exhibiting a rising R-curve.
Note 2—One difference between the procedures in these test methods and test methods such as Test Method E 399, which measure fracture toughness, KIc, by one set of specific operational procedures, is that Test Method E 399 focuses on the start of the crack extension from a fatigue precrack for metallic materials. In these test methods the test methods for advanced ceramics make use of either a sharp precrack formed via bridge loading (pb) or via Knoop indent (sc) prior to the test, or a crack formed during the test (vb). Differences in test procedure and analysis may cause the values from each test method to be different. Therefore, fracture toughness values determined with these methods cannot be interchanged with KIc as defined in Test Method E 399 and may not be interchangeable with each other.
1.4 These test methods give fracture toughness values, KIpb, KIsc, KIvb, for specific conditions of environment, test rate and temperature. The fracture toughness values, KIpb, KIsc, and KIvb for a material can be functions of environment, test rate and temperature.
1.5 These test methods are intended primarily for use with advanced ceramics which are macroscopically homogeneous. Certain whisker- or particle-reinforced ceramics may also meet the macroscopic behavior assumptions.
1.6 These test methods are divided into three major parts and related sub parts as shown below. The first major part is the main body and provides general information on the test methods described, the applicability to materials comparison and qualification, and requirements and recommendations for fracture toughness testing. The second major part is composed of annexes that provide procedures, test specimen design, precracking, testing, and data analysis for each method. Annex A1 describes suggested test fixtures, Annex A2 describes the pb method, Annex A3 describes the sc method, and Annex A4 describes the vb method. The third major part consists of three appendices detailing issues related to the fractography and precracking used for the sc method. Main BodySectionScope1Referenced Documents2Terminology (including definitions, orientation and symbols)3Summary of Test Methods4Significance and Use5Interferences6Apparatus7Test Specimen Configurations, Dimensions and Preparations8General Procedures9Report (including reporting tables)10Precision and Bias11AnnexesTest Fixture GeometriesA1Special Requirements for Precracked Beam MethodA2Special Requirements for Surface Crack in Flexure MethodA3Special Requirements for Chevron Notch Flexure MethodA4AppendicesPrecrack Characterization, Surface Crack in Flexure MethodX1Complications in Interpreting Surface Crack in Flexure Precracks X2Alternative Precracking Procedure, Surface Crack in Flexure MethodX3
1.7 Values expres...

General Information

Status
Historical
Publication Date
09-Oct-2001
ICS
81.060.30 - Advanced ceramics
Technical Committee
C28 - Advanced Ceramics
Drafting Committee
C28.01 - Mechanical Properties and Performance
Current Stage
Ref Project

Relations

Replaces
ASTM C1421-01a - Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperatures
Effective Date
10-Oct-2001
Replaced By
ASTM C1421-01b(2007) - Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperature
Effective Date
01-Feb-2007
Referred By
ASTM D7779-20 - Standard Test Method for Determination of Fracture Toughness of Graphite at Ambient Temperature
Effective Date
10-Oct-2001
Referred By
ASTM F2094/F2094M-18a - Standard Specification for Silicon Nitride Bearing Balls
Effective Date
10-Oct-2001
Referred By
ASTM F2730/F2730M-18a - Standard Specification for Silicon Nitride Cylindrical Bearing Rollers
Effective Date
10-Oct-2001
Referred By
ASTM E2899-19e1 - Standard Test Method for Measurement of Initiation Toughness in Surface Cracks Under Tension and Bending
Effective Date
10-Oct-2001

Buy Standard

ASTM C1421-01b - Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient TemperatureASTM C1421-01b - Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperature
PreviousNext
Standard
ASTM C1421-01b - Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperature
English language
33 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: C 1421 – 01b
Standard Test Methods for
Determination of Fracture Toughness of Advanced Ceramics
1
at Ambient Temperature
This standard is issued under the fixed designation C1421; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
toughness values determined with these methods cannot be interchanged
1. Scope
with K as defined inTest Method E399 and may not be interchangeable
Ic
1.1 These test methods cover the fracture toughness deter-
with each other.
mination of K (precracked beam test specimen), K (surface
Ipb Isc
1.4 Thesetestmethodsgivefracturetoughnessvalues,K ,
Ipb
crack in flexure), and K (chevron-notched beam test speci-
Ivb
K , and K , for specific conditions of environment, test rate
Isc Ivb
men) of advanced ceramics at ambient temperature. The
andtemperature.Thefracturetoughnessvalues,K ,K ,and
Ipb Isc
fracture toughness values are determined using beam test
K for a material can be functions of environment, test rate
Ivb
specimens with a sharp crack. The crack is either a straight-
and temperature.
through crack (pb), or a semi-elliptical surface crack (sc), or it
1.5 These test methods are intended primarily for use with
is propagated in a chevron notch (vb).
advanced ceramics which are macroscopically homogeneous.
NOTE 1—Thetermsbend(ing)andflexurearesynonymousinthesetest
Certainwhisker-orparticle-reinforcedceramicsmayalsomeet
methods.
the macroscopic behavior assumptions.
1.2 These test methods determine fracture toughness values
1.6 These test methods are divided into three major parts
based on a force and crack length measurement (pb, sc), or a
andrelatedsubpartsasshownbelow.Thefirstmajorpartisthe
force measurement and an inferred crack length (vb). In
main body and provides general information on the test
general, the fracture toughness is determined from maximum
methods described, the applicability to materials comparison
force. Applied force and displacement or an alternative (for
and qualification, and requirements and recommendations for
example, time) are recorded for the pb test specimen and vb
fracture toughness testing. The second major part is composed
test specimen.
of annexes that provide procedures, test specimen design,
1.3 These test methods are applicable to materials with
precracking, testing, and data analysis for each method.Annex
either flat or with rising R-curves. The fracture toughness
A1 describes suggested test fixtures, Annex A2 describes the
measured from stable crack extension may be different than
pb method,AnnexA3 describes the sc method, andAnnexA4
that measured from unstable crack extension. This difference
describes the vb method.The third major part consists of three
may be more pronounced for materials exhibiting a rising
appendices detailing issues related to the fractography and
R-curve.
precracking used for the sc method.
Main Body Section
NOTE 2—One difference between the procedures in these test methods
Scope 1
and test methods such as Test Method E399, which measure fracture
Referenced Documents 2
toughness, K , by one set of specific operational procedures, is that Test
Ic
Terminology (including definitions, orientation and symbols) 3
Method E399 focuses on the start of crack extension from a fatigue
Summary of Test Methods 4
precrack for metallic materials. In these test methods the test methods for Significance and Use 5
Interferences 6
advanced ceramics make use of either a sharp precrack formed via bridge
Apparatus 7
flexure (pb) or via Knoop indent (sc) prior to the test, or a crack formed
Test Specimen Configurations, Dimensions and Preparations 8
during the test (vb). Differences in test procedure and analysis may cause
General Procedures 9
the values from each test method to be different. Therefore, fracture
Report (including reporting tables) 10
Precision and Bias 11
Annexes
Test Fixture Geometries A1
1
Special Requirements for Precracked Beam Method A2
This test method is under the jurisdiction of ASTM Committee C28 on
Special Requirements for Surface Crack in Flexure Method A3
Advanced Ceramics and is the direct responsibility of Subcommittee C28.01 on
Special Requirements for Chevron Notch Flexure Method A4
Properties and Performance .
Appendices
Current edition approved Oct. 10, 2001. Published January 2002. Originally
Precrack Characterization, Surface Crack in Flexure Method X1
published as C1421-99. Last previous edition C1421-01a.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

---------------------- Page: 1 ----------------------
C 1421 – 01b
3.1.5 slow c
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.

This May Also Interest You

ASTM
ASTM C1674-23(Test Method)
Standard Test Method for Flexural Strength of Advanced Ceramics with Engineered Porosity (Honeycomb Cellular Channels) at Ambient Temperatures

SIGNIFICANCE AND USE
5.1 This test method is used to determine the mechanical properties in flexure of engineered ceramic components with multiple longitudinal hollow channels, commonly described as “honeycomb” channel architectures. The components generally have 30 % or more porosity and the cross-sectional dimensions of the honeycomb channels are on the order of 1 mm or greater.  
5.2 The experimental data and calculated strength values from this test method are used for material and structural development, product characterization, design data, quality control, and engineering/production specifications.
Note 1: Flexure testing is the preferred method for determining the nominal “tensile fracture” strength of these components, as compared to a compression (crushing) test. A nominal tensile strength is required, because these materials commonly fail in tension under thermal gradient stresses. A true tensile test is difficult to perform on these honeycomb specimens because of gripping and alignment challenges.  
5.3 The mechanical properties determined by this test method are both material and architecture dependent, because the mechanical response and strength of the porous test specimens are determined by a combination of inherent material properties and microstructure and the architecture of the channel porosity [porosity fraction/relative density, channel geometry (shape, dimensions, cell wall thickness, etc.), anisotropy and uniformity, etc.] in the specimen. Comparison of test data must consider both differences in material/composition properties as well as differences in channel porosity architecture between individual specimens and differences between and within specimen lots.  
5.4 Test Method A is a user-defined specimen geometry with a choice of four-point or three-point flexure testing geometries. It is not possible to define a single fixed specimen geometry for flexure testing of honeycombs, because of the wide range of honeycomb architectures and cell sizes and consid...
SCOPE
1.1 This test method covers the determination of the flexural strength (modulus of rupture in bending) at ambient conditions of advanced ceramic structures with 2-dimensional honeycomb channel architectures.  
1.2 The test method is focused on engineered ceramic components with longitudinal hollow channels, commonly called “honeycomb” channels (see Fig. 1). The components generally have 30 % or more porosity and the cross-sectional dimensions of the honeycomb channels are on the order of 1 mm or greater. Ceramics with these honeycomb structures are used in a wide range of applications (catalytic conversion supports (1),2 high temperature filters (2, 3), combustion burner plates (4), energy absorption and damping (5), etc.). The honeycomb ceramics can be made in a range of ceramic compositions—alumina, cordierite, zirconia, spinel, mullite, silicon carbide, silicon nitride, graphite, and carbon. The components are produced in a variety of geometries (blocks, plates, cylinders, rods, rings).
FIG. 1 General Schematics of Typical Honeycomb Ceramic Structures  
1.3 The test method describes two test specimen geometries for determining the flexural strength (modulus of rupture) for a porous honeycomb ceramic test specimen (see Fig. 2):
FIG. 2 Flexure Loading Configurations  
L = Outer Span Length (for Test Method A, L = User defined; for Test Method B, L = 90 mm)
Note 1: 4-Point-1/4 Loading for Test Methods A1 and B.
Note 2: 3-Point Loading for Test Method A2.  
1.3.1 Test Method A—A 4-point or 3-point bending test with user-defined specimen geometries, and  
1.3.2 Test Method B—A 4-point-1/4 point bending test with a defined rectangular specimen geometry (13 mm × 25 mm × > 116 mm) and a 90 mm outer support span geometry suitable for cordierite and silicon carbide honeycombs with small cell sizes.  
1.4 The test specimens are stressed to failure and the breaking force value, specimen and cell dimensions, and loa...

  • Standard
    25 pages
    English language
    sale 15% off
  • Standard
    25 pages
    English language
    sale 15% off
ASTM
ASTM C1341-13(2023)(Test Method)
Standard Test Method for Flexural Properties of Continuous Fiber-Reinforced Advanced Ceramic Composites

SIGNIFICANCE AND USE
5.1 This test method is used for material development, quality control, and material flexural specifications. Although flexural test methods are commonly used to determine design strengths of monolithic advanced ceramics, the use of flexure test data for determining tensile or compressive properties of CFCC materials is strongly discouraged. The nonuniform stress distributions in the flexure test specimen, the dissimilar mechanical behavior in tension and compression for CFCCs, low shear strengths of CFCCs, and anisotropy in fiber architecture all lead to ambiguity in using flexure results for CFCC material design data (1-4).3 Rather, uniaxial-forced tensile and compressive tests are recommended for developing CFCC material design data based on a uniformly stressed test condition.  
5.2 In this test method, the flexure stress is computed from elastic beam theory with the simplifying assumptions that the material 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 calculate a flexural strength value, but limit the application to comparative type testing such as used for material development, quality control, and flexure specifications. Such comparative testing requires consistent and standardized test conditions, that is, test specimen geometry/thickness, strain rates, and atmospheric/test conditions.  
5.3 Unlike monolithic advanced ceramics which fracture catastrophically from a single dominant flaw, CFCCs generally experience “graceful” fracture from a cumulative damage process. Therefore, the volume of material subjected to a uniform flexural stress may not be as significant a factor in determining the flexural strength of CFCCs. However, the need to test a statistically significant number of flexure test specimens is not eliminated. Because of the probabilistic nature of the strength of the brittle matrices and of the ceramic...
SCOPE
1.1 This test method covers the determination of flexural properties of continuous fiber-reinforced ceramic composites in the form of rectangular bars formed directly or cut from sheets, plates, or molded shapes. Three test geometries are described as follows:  
1.1.1 Test Geometry I—A three-point loading system utilizing center point force application on a simply supported beam.  
1.1.2 Test Geometry IIA—A four-point loading system utilizing two force application points equally spaced from their adjacent support points, with a distance between force application points of one-half of the support span.  
1.1.3 Test Geometry IIB—A four-point loading system utilizing two force application points equally spaced from their adjacent support 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: unidirectional (1D), bidirectional (2D), tridirectional (3D), and other continuous fiber architectures. In addition, this test method may also be used with glass (amorphous) matrix composites with continuous fiber reinforcement. However, flexural strength cannot be determined for those materials that do not break or fail by tension or compression in the outer fibers. This test method does not directly address discontinuous fiber-reinforced, whisker-reinforced, or particulate-reinforced ceramics. Those types 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 at elevated temperatures. At elevated temperatures, a suitable furnace is necessary for heating and holding the test specimens at the desired testing temperatures.  
1.4 This test method includes the following:    
Section    
Scope  
1  
Referenced Documents  
2  
Terminology  
3  
Summary of Test Method  
...

  • Standard
    21 pages
    English language
    sale 15% off
ASTM
ASTM C1869-18(2023)(Test Method)
Standard Test Method for Open-Hole Tensile Strength of Fiber-Reinforced Advanced Ceramic Composites

SIGNIFICANCE AND USE
5.1 Open-hole tests of composites are used for material and design development for the engineering application of composite materials (5-11). The presence of an open hole in a composite component reduces the cross-sectional area available to carry an applied force, creates stress concentrations, and creates new edges where delamination may occur. Standardized open-hole tests for composite materials can provide useful information about how a composite material may perform in an open-hole application and how to design the composite for notches and holes.  
5.2 The test method defines two baseline test specimen geometries and a test procedure for producing comparable, reproducible OHT test data. The test method is designed to produce OHT strength data for structural design allowables, material specifications, material development and comparison, material characterization, and quality assurance. The mechanical properties that may be calculated from this test method include:  
5.2.1 The open-hole (notched) tensile strength (SOHTx) for test specimen with a hole diameter x (mm).  
5.2.2 The net section tensile strength (SNSx) for a test specimen with a hole diameter x (mm).  
5.2.3 The proportional limit stress (σ0) for an OHT specimen with a given hole diameter.  
5.2.4 The stress response of the OHT test specimen, as shown by the stress-time or stress-displacement plot.  
5.3 Open-hole tensile tests provide information on the strength and deformation of materials with defined through-holes under uniaxial tensile stresses. Material factors that influence the OHT composite strength include the following: material composition, methods of composite fabrication, reinforcement architecture (including reinforcement volume, tow filament count and end-count, architecture structure, and laminate stacking sequence), and porosity content. Test specimen factors of influence are: specimen geometry (including hole diameter, width-to-diameter ratio, and diameter-to-thickness rati...
SCOPE
1.1 This test method determines the open-hole (notched) tensile strength of continuous fiber-reinforced ceramic matrix composite (CMC) test specimens with a single through-hole of defined diameter (either 6 mm or 3 mm). The open-hole tensile (OHT) test method determines the effect of the single through-hole on the tensile strength and stress response of continuous fiber-reinforced CMCs at ambient temperature. The OHT strength can be compared to the tensile strength of an unnotched test specimen to determine the effect of the defined open hole on the tensile strength and the notch sensitivity of the CMC material. If a material is notch sensitive, then the OHT strength of a material varies with the size of the through-hole. Commonly, larger holes introduce larger stress concentrations and reduce the OHT strength.  
1.2 This test method defines two baseline OHT test specimen geometries and a test procedure, based on Test Methods C1275 and D5766/D5766M. A flat, straight-sided ceramic composite test specimen with a defined laminate fiber architecture contains a single through-hole (either 6 mm or 3 mm in diameter), centered by length and width in the defined gage section (Fig. 1). A uniaxial, monotonic tensile test is performed along the defined test reinforcement axis at ambient temperature, measuring the applied force versus time/displacement in accordance with Test Method C1275. Measurement of the gage length extension/strain is optional, using extensometer/displacement transducers. Bonded strain gages are optional for measuring localized strains and assessing bending strains in the gage section.
FIG. 1 OHT Test Specimens A and B  
1.3 The open-hole tensile strength (SOHTx) for the defined hole diameter x (mm) is the calculated ultimate tensile strength based on the maximum applied force and the gross cross-sectional area, disregarding the presence of the hole, per common aerospace practice (see 4.4). The net section ...

  • Standard
    22 pages
    English language
    sale 15% off
ASTM
ASTM C1684-18(2023)(Test Method)
Standard Test Method for Flexural Strength of Advanced Ceramics at Ambient Temperature—Cylindrical Rod Strength

SIGNIFICANCE AND USE
4.1 This test method may be used for material development, quality control, characterization, and design data generation purposes. This test method is intended to be used with ceramics whose strength is 50 MPa (~7 ksi) or greater. The test method may also be used with glass test specimens, although Test Methods C158 is specifically designed to be used for glasses. This test method may be used with machined, drawn, extruded, and as-fired round specimens. This test method may be used with specimens that have elliptical cross section geometries.  
4.2 The flexure strength is computed based on simple beam theory with assumptions that the material is isotropic and homogeneous, the moduli of elasticity in tension and compression are identical, and the material is linearly elastic. The average grain size should be no greater than one-fiftieth of the rod diameter. The homogeneity and isotropy assumptions in the standard rule out the use of this test for continuous fiber-reinforced ceramics.  
4.3 Flexural strength of a group of test specimens is influenced by several parameters associated with the test procedure. Such factors include the loading rate, test environment, specimen size, specimen preparation, and test fixtures (1-3).3 This method includes specific specimen-fixture size combinations, but permits alternative configurations within specified limits. These combinations were chosen to be practical, to minimize experimental error, and permit easy comparison of cylindrical rod strengths with data for other configurations. Equations for the Weibull effective volume and Weibull effective surface are included.  
4.4 The flexural strength of a ceramic material is dependent on both its inherent resistance to fracture and the size and severity of flaws in the material. Flaws in rods may be intrinsically volume-distributed throughout the bulk. Some of these flaws by chance may be located at or near the outer surface. Flaws may alternatively be intrinsically surface-distrib...
SCOPE
1.1 This test method is for the determination of flexural strength of rod-shaped specimens of advanced ceramic materials at ambient temperature. In many instances it is preferable to test round specimens rather than rectangular bend specimens, especially if the material is fabricated in rod form. This method permits testing of machined, drawn, or as-fired rod-shaped specimens. It allows some latitude in the rod sizes and cross section shape uniformity. Rod diameters between 1.5 and 8 mm and lengths from 25 to 85 mm are recommended, but other sizes are permitted. Four-point-1/4-point as shown in Fig. 1 is the preferred testing configuration. Three-point loading is permitted. This method describes the apparatus, specimen requirements, test procedure, calculations, and reporting requirements. The method is applicable to monolithic or particulate- or whisker-reinforced ceramics. It may also be used for glasses. It is not applicable to continuous fiber-reinforced ceramic composites.
FIG. 1 Four-Point-1/4-Point Flexure Loading Configuration  
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.3 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 appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

  • Standard
    21 pages
    English language
    sale 15% off
ASTM
ASTM C1326-13(2023)(Test Method)
Standard Test Method for Knoop Indentation Hardness of Advanced Ceramics

SIGNIFICANCE AND USE
5.1 For advanced ceramics, Knoop indenters are used to create indentations. The surface projection of the long diagonal is measured with optical microscopes.  
5.2 The Knoop indentation hardness is one of many properties that is used to characterize advanced ceramics. Attempts have been made to relate Knoop indentation hardness to other hardness scales, but no generally accepted methods are available. Such conversions are limited in scope and should be used with caution, except for special cases where a reliable basis for the conversion has been obtained by comparison tests.  
5.3 For advanced ceramics, the Knoop indentation is often preferred to the Vickers indentation since the Knoop long diagonal length is 2.8 times longer than the Vickers diagonal for the same force, and cracking is much less of a problem (1).5 On the other hand, the long slender tip of the Knoop indentation is more difficult to precisely discern, especially in materials with low contrast. The indentation forces chosen in this test method are designed to produce indentations as large as may be possible with conventional microhardness equipment, yet not so large as to cause cracking.  
5.4 The Knoop indentation is shallower than Vickers indentations made at the same force. Knoop indents may be useful in evaluating coating hardnesses.  
5.5 Knoop hardness is calculated from the ratio of the applied force divided by the projected indentation area on the specimen surface. It is assumed that the elastic springback of the narrow diagonal is negligible. (Vickers indenters are also used to measure hardness, but Vickers hardness is calculated from the ratio of applied force to the area of contact of the four faces of the undeformed indenter.)  
5.6 A full hardness characterization includes measurements over a broad range of indentation forces. Knoop hardness of ceramics usually decreases with increasing indentation size or indentation force such as that shown in Fig. 1.6 The trend is known as the in...
SCOPE
1.1 This test method covers the determination of the Knoop indentation hardness of advanced ceramics. In this test, a pointed, rhombic-based, pyramidal diamond indenter of prescribed shape is pressed into the surface of a ceramic with a predetermined force to produce a relatively small, permanent indentation. The surface projection of the long diagonal of the permanent indentation is measured using a light microscope. The length of the long diagonal and the applied force are used to calculate the Knoop hardness which represents the material’s resistance to penetration by the Knoop indenter.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 Units—When Knoop and Vickers hardness tests were developed, the force levels were specified in units of grams-force (gf) and kilograms-force (kgf). This standard specifies the units of force and length in the International System of Units (SI); that is, force in newtons (N) and length in mm or μm. However, because of the historical precedent and continued common usage, force values in gf and kgf units are occasionally provided for information. This test method specifies that Knoop hardness be reported either in units of GPa or as a dimensionless Knoop hardness number.  
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 appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

  • Standard
    10 pages
    English language
    sale 15% off
ASTM
ASTM C1495-16(2023)(Test Method)
Standard Test Method for Effect of Surface Grinding on Flexure Strength of Advanced Ceramics

SIGNIFICANCE AND USE
5.1 Surface grinding can cause a significant decrease4 in the flexure strength of advanced ceramic materials. The magnitude of the loss in strength is determined by the grinding conditions and the response of the material. This test method can be used to obtain a detailed characterization of the relationship between grinding conditions and flexure strength for an advanced ceramic material. The effect on flexure strength of varying a single grinding parameter or several grinding parameters can be measured. The method may also be used to compare and rank different materials according to their response to one or more different grinding conditions. Results obtained by this method can be used to develop an optimum grinding process with respect to maximizing material removal rate for a specified flexure strength requirement. The test method can assist in the development of improved grinding-damage-tolerant ceramic materials. It may also be used for quality control purposes to monitor and assure the consistency of a grinding process in the fabrication of parts from advanced ceramic materials. The test method is applicable to grinding methods that generate a planar surface and is not directly applicable to grinding methods that produce non-planar surfaces such as cylindrical and centerless grinding.
SCOPE
1.1 This test method covers the determination of the effect of surface grinding on the flexure strength of advanced ceramics. Surface grinding of an advanced ceramic material can introduce microcracks and other changes in the near surface layer, generally referred to as damage (see Fig. 1 and Ref. (1)).2 Such damage can result in a change—most often a decrease—in flexure strength of the material. The degree of change in flexure strength is determined by both the grinding process and the response characteristics of the specific ceramic material. This method compares the flexure strength of an advanced ceramic material after application of a user-specified surface grinding process with the baseline flexure strength of the same material. The baseline flexure strength is obtained after application of a surface grinding process specified in this standard. The baseline flexure strength is expected to approximate closely the inherent strength of the material. The flexure strength is measured by means of ASTM flexure test methods.
FIG. 1 Microcracks Associated with Grinding (Ref. (1))2  
1.2 Flexure test methods used to determine the effect of surface grinding are C1161 Test Method for Flexure Strength of Advanced Ceramics at Ambient Temperatures and C1211 Test Method for Flexure Strength of Advanced Ceramics at Elevated Temperatures.  
1.3 Materials covered in this standard are those advanced ceramics that meet criteria specified in flexure testing standards C1161 and C1211.  
1.4 The flexure test methods supporting this standard (C1161 and C1211) require test specimens that have a rectangular cross section, flat surfaces, and that are fabricated with specific dimensions and tolerances. Only grinding processes that are capable of generating the specified flat surfaces, that is, planar grinding modes, are suitable for evaluation by this method. Among the applicable machine types are horizontal and vertical spindle reciprocating surface grinders, horizontal and vertical spindle rotary surface grinders, double disk grinders, and tool-and-cutter grinders. Incremental cross-feed, plunge, and creep-feed grinding methods may be used.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 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 appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.7 This international standard was develop...

  • Standard
    12 pages
    English language
    sale 15% off
ASTM
ASTM C1211-18(2023)(Test Method)
Standard Test Method for Flexural Strength of Advanced Ceramics at Elevated Temperatures

SIGNIFICANCE AND USE
4.1 This test method may be used for material development, quality control, characterization, and design data generation purposes. This test method is intended to be used with ceramics whose flexural strength is ∼50 MPa (∼7 ksi) or greater.  
4.2 The flexure stress is computed based on simple beam theory, with assumptions that the material is isotropic and homogeneous, the moduli of elasticity in tension and compression are identical, and the material is linearly elastic. The average grain size should be no greater than 1/50 of the beam thickness. The homogeneity and isotropy assumptions in the test method rule out the use of it for continuous fiber-reinforced composites for which Test Method C1341 is more appropriate.  
4.3 The flexural strength of a group of test specimens is influenced by several parameters associated with the test procedure. Such factors include the testing rate, test environment, specimen size, specimen preparation, and test fixtures. Specimen and fixture sizes were chosen to provide a balance between the practical configurations and resulting errors as discussed in Test Method C1161, and Refs (1-3).4 Specific fixture and specimen configurations were designated in order to permit the ready comparison of data without the need for Weibull size scaling.  
4.4 The flexural strength of a ceramic material is dependent on both its inherent resistance to fracture and the size and severity of flaws. Variations in these cause a natural scatter in test results for a sample of test specimens. Fractographic analysis of fracture surfaces, although beyond the scope of this test method, is highly recommended for all purposes, especially if the data will be used for design as discussed in Ref (4) and Practices C1322 and C1239.  
4.5 This method determines the flexural strength at elevated temperature and ambient environmental conditions at a nominal, moderately fast testing rate. The flexural strength under these conditions may or may not necessarily be the...
SCOPE
1.1 This test method covers determination of the flexural strength of advanced ceramics at elevated temperatures.2 Four-point-1/4-point and three-point loadings with prescribed spans are the standard as shown in Fig. 1. Rectangular specimens of prescribed cross-section are used with specified features in prescribed specimen-fixture combinations. Test specimens may be 3 by 4 by 45 to 50 mm in size that are tested on 40-mm outer span four-point or three-point fixtures. Alternatively, test specimens and fixture spans half or twice these sizes may be used. The test method permits testing of machined or as-fired test specimens. Several options for machining preparation are included: application matched machining, customary procedures, or a specified standard procedure. This test method describes the apparatus, specimen requirements, test procedure, calculations, and reporting requirements. The test method is applicable to monolithic or particulate- or whisker-reinforced ceramics. It may also be used for glasses. It is not applicable to continuous fiber-reinforced ceramic composites.  
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.3 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 appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

  • Standard
    17 pages
    English language
    sale 15% off
ASTM
ASTM C1323-22(Test Method)
Standard Test Method for Ultimate Strength of Advanced Ceramics with Diametrally Compressed C-Ring Specimens at Ambient Temperature

SIGNIFICANCE AND USE
4.1 This test method may be used for material development, material comparison, quality assurance, and characterization. Extreme care should be exercised when generating design data.  
4.2 For a C-ring under diametral compression, the maximum tensile stress occurs at the outer surface. Hence, the C-ring specimen loaded in compression will predominately evaluate the strength distribution and flaw population(s) on the external surface of a tubular component in the hoop direction. Accordingly, the condition of the inner surface may be of lesser consequence in specimen preparation and testing.
Note 1: A C-ring in tension or an O-ring in compression may be used to evaluate the internal surface.  
4.2.1 The flexure stress is computed based on simple curved beam theory (1-5).3 It is assumed that the material is isotropic and homogeneous, the moduli of elasticity are identical in compression or tension, and the material is linearly elastic. These homogeneity and isotropy assumptions preclude the use of this standard for continuous fiber reinforced composites. Average grain size(s) should be no greater than one fiftieth (1/50 ) of the C-ring thickness. The curved beam stress solution from engineering mechanics is in good agreement (within 2 %) with an elasticity solution as discussed in (6) for the test specimen geometries recommended for this standard. The curved beam stress equations are simple and straightforward, and therefore it is relatively easy to integrate the equations for calculations for effective area or effective volume for Weibull analyses as discussed in Appendix X1.  
4.2.2 The simple curved beam and theory of elasticity stress solutions both are two-dimensional plane stress solutions. They do not account for stresses in the axial (parallel to b) direction, or variations in the circumferential (hoop, σθ) stresses through the width (b) of the test piece. The variations in the circumferential stresses increase with increases in width (b) and ring thicknes...
SCOPE
1.1 This test method covers the determination of ultimate strength under monotonic loading of advanced ceramics in tubular form at ambient temperatures. The ultimate strength as used in this test method refers to the strength obtained under monotonic compressive loading of C-ring specimens such as shown in Fig. 1, where monotonic refers to a continuous nonstop test rate with no reversals from test initiation to final fracture. This method permits a range of sizes and shapes since test specimens may be prepared from a variety of tubular structures. The method may be used with microminiature test specimens.
FIG. 1 C-Ring Test Geometry with Defining Geometry and Reference Angle (θ) for the Point of Fracture Initiation on the Circumference  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.2.1 Values expressed in this test method are in accordance with the International System of Units (SI) and IEEE/ASTM SI 10.  
1.3 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 appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

  • Standard
    8 pages
    English language
    sale 15% off
  • Standard
    8 pages
    English language
    sale 15% off
ASTM
ASTM C1292-22(Test Method)
Standard Test Method for Shear Strength of Continuous Fiber-Reinforced Advanced Ceramics at Ambient Temperatures

SIGNIFICANCE AND USE
5.1 Continuous fiber-reinforced ceramic composites can be candidate materials for structural applications requiring high degrees of wear and corrosion resistance, and damage tolerance at high temperatures.  
5.2 Shear tests provide information on the strength and deformation of materials under shear stresses.  
5.3 This test method may be used for material development, material comparison, quality assurance, characterization, and design data generation.  
5.4 For quality control purposes, results derived from standardized shear test specimens may be considered indicative of the response of the material from which they were taken for given primary processing conditions and post-processing heat treatments.
SCOPE
1.1 This test method covers the determination of shear strength of continuous fiber-reinforced ceramic composites (CFCCs) at ambient temperature. The test methods addressed are (1) the compression of a double-notched test specimen to determine interlaminar shear strength, and (2) the Iosipescu test method to determine the shear strength in any one of the material planes of laminated composites. Test specimen fabrication methods, testing modes (load or displacement control), testing rates (load rate or displacement rate), data collection, and reporting procedures are addressed.  
1.2 This test method is used for testing advanced ceramic or glass matrix composites with continuous fiber reinforcement having unidirectional (1D) or bidirectional (2D) fiber architecture. This test method does not address composites with 3D fiber architecture or discontinuous fiber-reinforced, whisker-reinforced, or particulate-reinforced ceramics.  
1.3 The values stated in SI units are to be regarded as the standard and are in accordance with 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 appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in 8.1 and 8.2.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

  • Standard
    9 pages
    English language
    sale 15% off
  • Standard
    9 pages
    English language
    sale 15% off
ASTM
ASTM C1469-22(Test Method)
Standard Test Method for Shear Strength of Joints of Advanced Ceramics at Ambient Temperature

SIGNIFICANCE AND USE
5.1 Advanced ceramics can be candidate materials for structural applications requiring high degrees of wear and corrosion resistance, often at elevated temperatures.  
5.2 Joints are produced to enhance the performance and applicability of materials. While the joints between similar materials are generally made for manufacturing complex parts and repairing components, those involving dissimilar materials usually are produced to exploit the unique properties of each constituent in the new component. Depending on the joining process, the joint region may be the weakest part of the component. Since under mixed-mode and shear loading the load transfer across the joint requires reasonable shear strength, it is important that the quality and integrity of joint under in-plane shear forces be quantified. Shear strength data are also needed to monitor the development of new and improved joining techniques.  
5.3 Shear tests provide information on the strength and deformation of materials under shear stresses.  
5.4 This test method may be used for material development, material comparison, quality assurance, characterization, and design data generation.  
5.5 For quality control purposes, results derived from standardized shear test specimens may be considered indicative of the response of the material from which they were taken for given primary processing conditions and post-processing heat treatments.
SCOPE
1.1 This test method covers the determination of shear strength of joints in advanced ceramics at ambient temperature using asymmetrical four-point flexure. Test specimen geometries, test specimen fabrication methods, testing modes (that is, force or displacement control), testing rates (that is, force or displacement rate), data collection, and reporting procedures are addressed.  
1.2 This test method is used to measure shear strength of ceramic joints in test specimens extracted from larger joined pieces by machining. Test specimens fabricated in this way are not expected to warp due to the relaxation of residual stresses but are expected to be much straighter and more uniform dimensionally than butt-jointed test specimens prepared by joining two halves, which is not recommended. In addition, this test method is intended for joints, which have either low or intermediate strengths with respect to the substrate material to be joined. Joints with high strengths should not be tested by this test method because of the high probability of invalid tests resulting from fractures initiating at the reaction points rather than in the joint. Determination of the shear strength of joints using this test method is appropriate particularly for advanced ceramic matrix composite materials but also may be useful for monolithic advanced ceramic materials.  
1.3 Values expressed in this test method are in accordance with the International System of Units (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 appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are noted in 8.1.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

  • Standard
    8 pages
    English language
    sale 15% off
  • Standard
    8 pages
    English language
    sale 15% off