On the Effect of Local Grain-Boundary Chemistry on the Macroscopic Mechanical Properties of a High Purity Y2O3-Al2O3-Containing Silicon Nitride Ceramic [electronic resource] : Role of Oxygen
- Washington, D.C. : United States. Dept. of Energy, 2004. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- PDF-file: 9 pages; size: 9 Mbytes
- Additional Creators:
- Lawrence Berkeley National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- The effects of grain-boundary chemistry on the mechanical properties were investigated on high-purity silicon nitride ceramics, specifically involving the role of oxygen. Varying the grain-boundary oxygen content, by 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, and consequently toughening 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.
- Published through SciTech Connect., 11/23/2004., "ucrl-conf-208303", Presented at: 2004 MRS Fall Meeting, Boston, MA, United States, Nov 29 - Dec 03, 2004., and Ritchie, R O; Hoffman, M J; Ziegler, A; McNaney, J M.
- Funding Information:
View MARC record | catkey: 14447660