ASTM C1368-18
(Test Method)Standard Test Method for Determination of Slow Crack Growth Parameters of Advanced Ceramics by Constant Stress Rate Strength Testing at Ambient Temperature
Standard Test Method for Determination of Slow Crack Growth Parameters of Advanced Ceramics by Constant Stress Rate Strength Testing at Ambient Temperature
SIGNIFICANCE AND USE
4.1 For many structural ceramic components in service, their use is often limited by lifetimes that are controlled by a process of SCG. This test method provides the empirical parameters for appraising the relative SCG susceptibility of ceramic materials under specified environments. Furthermore, this test method may establish the influences of processing variables and composition on SCG as well as on strength behavior of newly developed or existing materials, thus allowing tailoring and optimizing material processing for further modification. In summary, this test method may be used for material development, quality control, characterization, and limited design data generation purposes. The conventional analysis of constant stress rate testing is based on a number of critical assumptions, the most important of which are listed in the next paragraphs.
4.2 The flexural stress computation for the rectangular beam test specimens or the equibiaxial disk flexure test specimens is based on simple beam theory, with the 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 beam thickness.
4.3 The test specimen sizes and fixtures for rectangular beam test specimens should be in accordance with Test Method C1161, which provides a balance between practical configurations and resulting errors, as discussed in Refs (4, 5). Only four-point test configuration is allowed in this test method for rectangular beam specimens. Three-point test configurations are not permitted. The test specimen sizes and fixtures for disk test specimens tested in ring-on-ring flexure should be chosen in accordance with Test Method C1499. The test specimens for direct tension strength testing should be chosen in accordance with Test Method C1273.
4.4 The SCG parameters (n and D) are determined by fitting the measured ...
SCOPE
1.1 This test method covers the determination of slow crack growth (SCG) parameters of advanced ceramics by using constant stress rate rectangular beam flexural testing, ring-on-ring biaxial disk flexural testing, or direct tensile strength, in which strength is determined as a function of applied stress rate in a given environment at ambient temperature. The strength degradation exhibited with decreasing applied stress rate in a specified environment is the basis of this test method which enables the evaluation of slow crack growth parameters of a material.
Note 1: This test method is frequently referred to as “dynamic fatigue” testing (1-3)2 in which the term “fatigue” is used interchangeably with the term “slow crack growth.” To avoid possible confusion with the “fatigue” phenomenon of a material which occurs exclusively under cyclic loading, as defined in Terminology E1823, this test method uses the term “constant stress rate testing” rather than “dynamic fatigue” testing.
Note 2: In glass and ceramics technology, static tests of considerable duration are called “static fatigue” tests, a type of test designated as stress rupture (See Terminology E1823).
1.2 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.
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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.
Designation: C1368 − 18
Standard Test Method for
Determination of Slow Crack Growth Parameters of
Advanced Ceramics by Constant Stress Rate Strength
1
Testing at Ambient Temperature
This standard is issued under the fixed designation C1368; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
3
1.1 This test method covers the determination of slow crack 2.1 ASTM Standards:
growth (SCG) parameters of advanced ceramics by using C1145 Terminology of Advanced Ceramics
constant stress rate rectangular beam flexural testing, ring-on- C1161 Test Method for Flexural Strength of Advanced
ring biaxial disk flexural testing, or direct tensile strength, in Ceramics at Ambient Temperature
whichstrengthisdeterminedasafunctionofappliedstressrate C1239 Practice for Reporting Uniaxial Strength Data and
in a given environment at ambient temperature. The strength Estimating Weibull Distribution Parameters forAdvanced
degradation exhibited with decreasing applied stress rate in a Ceramics
specified environment is the basis of this test method which C1273 Test Method for Tensile Strength of Monolithic
enables the evaluation of slow crack growth parameters of a Advanced Ceramics at Ambient Temperatures
material. C1322 Practice for Fractography and Characterization of
Fracture Origins in Advanced Ceramics
NOTE 1—This test method is frequently referred to as “dynamic
2
C1499 Test Method for Monotonic Equibiaxial Flexural
fatigue” testing (1-3) in which the term “fatigue” is used interchangeably
Strength of Advanced Ceramics at Ambient Temperature
with the term “slow crack growth.” To avoid possible confusion with the
“fatigue”phenomenonofamaterialwhichoccursexclusivelyundercyclic
E4 Practices for Force Verification of Testing Machines
loading, as defined in Terminology E1823, this test method uses the term
E6 Terminology Relating to Methods of Mechanical Testing
“constant stress rate testing” rather than “dynamic fatigue” testing.
E337 Test Method for Measuring Humidity with a Psy-
NOTE 2—In glass and ceramics technology, static tests of considerable
chrometer (the Measurement of Wet- and Dry-Bulb Tem-
duration are called “static fatigue” tests, a type of test designated as stress
rupture (See Terminology E1823). peratures)
E1823 TerminologyRelatingtoFatigueandFractureTesting
1.2 Values expressed in this test method are in accordance
IEEE/ASTM SI 10 American National Standard for Use of
withtheInternationalSystemofUnits(SI)andIEEE/ASTMSI
theInternationalSystemofUnits(SI):TheModernMetric
10.
System
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3. Terminology
responsibility of the user of this standard to establish appro-
3.1 Definitions:
priate safety, health, and environmental practices and deter-
3.1.1 The terms described in Terminologies C1145, E6, and
mine the applicability of regulatory limitations prior to use.
E1823 are applicable to this test method. Specific terms
1.4 This international standard was developed in accor-
relevant to this test method are as follows:
dance with internationally recognized principles on standard-
3.1.2 advanced ceramic, n—a highly engineered, high-
ization established in the Decision on Principles for the
performance, predominately nonmetallic, inorganic, ceramic
Development of International Standards, Guides and Recom-
material having specific functional attributes. (C1145)
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee. 3.1.3 constant stress rate,σ˙,n—a constant rate of maximum
stress applied to a specified beam by using either a constant
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loading or constant displacement rate of a testing machine.
This test method is under the jurisdiction of ASTM Committee C28 on
Advanced Ceramics and is the direct responsibility of Subcommittee C28.01 on
Mechanical Properties and Performance.
Current edition approved Jan. 1, 2018. Published January 2018. Originally
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approved in 1997. Last previous edition approved in 2017 as C1368 – 10 (2017). For referenced ASTM standards, visit the ASTM website, www.astm.org, or
DOI: 10.1520/C1368-18. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
2
The boldface numbers in parentheses refer to the list of references at the end of Standards volume information, refer to the standard’s Document Summary page on
this standard. the ASTM website.
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...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it 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 version
of the standard as published by ASTM is to be considered the official document.
Designation: C1368 − 10 (Reapproved 2017) C1368 − 18
Standard Test Method for
Determination of Slow Crack Growth Parameters of
Advanced Ceramics by Constant Stress-Rate Stress Rate
1
Strength Testing at Ambient Temperature
This standard is issued under the fixed designation C1368; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*Scope
1.1 This test method covers the determination of slow crack growth (SCG) parameters of advanced ceramics by using constant
stress-rate stress rate rectangular beam flexural testing, or ring-on-ring biaxial disk flexural testing, or direct tensile strength, in
which strength is determined as a function of applied stress rate in a given environment at ambient temperature. The strength
degradation exhibited with decreasing applied stress rate in a specified environment is the basis of this test method which enables
the evaluation of slow crack growth parameters of a material.
2
NOTE 1—This test method is frequently referred to as “dynamic fatigue” testing (1-3) in which the term “fatigue” is used interchangeably with the
term “slow crack growth.” To avoid possible confusion with the “fatigue” phenomenon of a material which occurs exclusively under cyclic loading, as
defined in Terminology E1823, this test method uses the term “constant stress-rate stress rate testing” rather than “dynamic fatigue” testing.
NOTE 2—In glass and ceramics technology, static tests of considerable duration are called “static fatigue” tests, a type of test designated as stress-rupture
stress rupture (See Terminology E1823).
1.2 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 safety, health, and healthenvironmental 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.
2. Referenced Documents
3
2.1 ASTM Standards:
C1145 Terminology of Advanced Ceramics
C1161 Test Method for Flexural Strength of Advanced Ceramics at Ambient Temperature
C1239 Practice for Reporting Uniaxial Strength Data and Estimating Weibull Distribution Parameters for Advanced Ceramics
C1273 Test Method for Tensile Strength of Monolithic Advanced Ceramics at Ambient Temperatures
C1322 Practice for Fractography and Characterization of Fracture Origins in Advanced Ceramics
C1499 Test Method for Monotonic Equibiaxial Flexural Strength of Advanced Ceramics at Ambient Temperature
E4 Practices for Force Verification of Testing Machines
E6 Terminology Relating to Methods of Mechanical Testing
E337 Test Method for Measuring Humidity with a Psychrometer (the Measurement of Wet- and Dry-Bulb Temperatures)
E1823 Terminology Relating to Fatigue and Fracture Testing
IEEE/ASTM SI 10 American National Standard for Use of the International System of Units (SI): The Modern Metric System
3. Terminology
3.1 Definitions:
1
This test method is under the jurisdiction of ASTM Committee C28 on Advanced Ceramics and is the direct responsibility of Subcommittee C28.01 on Mechanical
Properties and Performance.
Current edition approved Feb. 1, 2017Jan. 1, 2018. Published February 2017January 2018. Originally approved in 1997. Last previous edition approved in 20102017 as
C1368 – 10.C1368 – 10 (2017). DOI: 10.1520/C1368-10R17.10.1520/C1368-18.
2
The boldface numbers in parentheses refer to the list of references at the end of this standard.
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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