ASTM C1368-18
Standard Test Method for Determination of Slow Crack Growth Parameters of Advanced Ceramics by Constant Stress Rate Strength Testing at Ambient Temperature

Standard No.

ASTM C1368-18

Release Date

2018

Published By

American Society for Testing and Materials (ASTM)

Latest

ASTM C1368-18

Scope

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 experimental data to a mathematical relationship between strength and applied stress rate, log σ_f = 1/(n+1) log σ˙ + log D. The basic underlying assumption on the derivation of this relationship is that SCG is governed by an empirical power-law crack velocity, v = A[K_I/K_IC]ⁿ (see Appendix X1).

ASTM C1368-18 Referenced Document

• ASTM C1145 Standard Terminology of Advanced Ceramics
• ASTM C1161 Standard Test Method for Flexural Strength of Advanced Ceramics at Ambient Temperature
• ASTM C1239 Standard Practice for Reporting Uniaxial Strength Data and Estimating Weibull Distribution Parameters for Advanced Ceramics*， 2018-07-01 Update
• ASTM C1273 Standard Test Method for Tensile Strength of Monolithic Advanced Ceramics at Ambient Temperatures
• ASTM C1322 Standard Practice for Fractography and Characterization of Fracture Origins in Advanced Ceramics
• ASTM C1499 Standard Test Method for Monotonic Equibiaxial Flexural Strength of Advanced Ceramics at Ambient Temperature*， 2019-07-01 Update
• ASTM E1823 Standard Terminology Relating to Fatigue and Fracture Testing
• ASTM E337 Standard Test Method for Measuring Humidity with a Psychrometer (the Measurement of Wet- and Dry-Bulb Temperatures)
• ASTM E4 Standard Practices for Force Verification of Testing Machines
• ASTM E6 Standard Terminology Relating to Methods of Mechanical Testing
• IEEE/ASTM SI 10 American National Standard for Metric Practice

ASTM C1368-18 history

• 2018 ASTM C1368-18 Standard Test Method for Determination of Slow Crack Growth Parameters of Advanced Ceramics by Constant Stress Rate Strength Testing at Ambient Temperature
• 2010 ASTM C1368-10(2017) Standard Test Method for Determination of Slow Crack Growth Parameters of Advanced Ceramics by Constant Stress-Rate Strength Testing at Ambient Temperature
• 2010 ASTM C1368-10 Standard Test Method for Determination of Slow Crack Growth Parameters of Advanced Ceramics by Constant Stress-Rate Strength Testing at Ambient Temperature
• 2006 ASTM C1368-06 Standard Test Method for Determination of Slow Crack Growth Parameters of Advanced Ceramics by Constant Stress-Rate Flexural Testing at Ambient Temperature
• 2001 ASTM C1368-01 Standard Test Method for Determination of Slow Crack Growth Parameters of Advanced Ceramics by Constant Stress-Rate Flexural Testing at Ambient Temperature
• 2000 ASTM C1368-00 Standard Test Method for Determination of Slow Crack Growth Parameters of Advanced Ceramics by Constant Stress-Rate Flexural Testing at Ambient Temperature