Abstract

For monolithic, grain-bridging ceramics, the crack-size dependence of the fatigue threshold during bridging zone development presents a difficulty in its application in design. This paper demonstrates how a fatigue threshold R-curve may express this crack-size dependence, analogous to the traditional fracture toughness R-curve, and may be used to predict the endurance limit and retained strength under cyclic loading conditions. Furthermore, the fatigue threshold R-curve may be deduced from the behavior of millimeter-scale, through-thickness, fatigue cracks via an accurately measured crack bridging stress profile. Both an alumina ceramic with large steady-state bridging zones (∼2 mm), where the predicted and experimentally measured fatigue threshold R-curves agree well over a range of crack sizes from 0.06 to 7 mm, and a (Y2O3-MgO)-doped Si3N4 ceramic, where bridging zones are much shorter (∼100 μm), are investigated. The approach provides a useful alternative to performing difficult short-crack fatigue experiments, particularly for materials with small bridging zones.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.