Abstract
ABSTRACTThe effects of grain-boundary chemistry on the mechanical properties of a high-purity silicon nitride ceramics were investigated, with specific emphasis on the role of oxygen. Variations in the grain-boundary oxygen content, through control of oxidizing heat treatments and sintering additives, was found to result in a transition in fracture mechanism from transgranular to intergranular fracture, with an associated increase in fracture toughness. This phenomenon is correlated to an oxygen-induced change in grain-boundary chemistry that appears to affect fracture by “weakening” the interface, facilitating debonding and crack advance along the boundaries, thereby enhancing the toughness by grain bridging. It is concluded that if the oxygen content in the thin grain-boundary films exceeds a lower limit, which is ∼0.87 equiv% oxygen content, then the interfacial structure and bonding characteristics favor intergranular debonding during crack propagation; otherwise, transgranular fracture ensues, with consequent low toughness.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
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.