On the Effect of Local Grain-Boundary Chemistry on the Macroscopic Mechanical Properties of a High Purity Y2O3-Al2O3-Containing Silicon Nitride Ceramic

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

Detail(s)

Original languageEnglish
Article numberP3.14
Journal / PublicationMaterials Research Society Symposium Proceedings
Volume839
Publication statusPublished - Nov 2004
Externally publishedYes

Conference

Title2004 MRS Fall Meeting
PlaceUnited States
CityBoston
Period29 November - 3 December 2004

Abstract

The 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. © 2005 Materials Research Society.

Citation Format(s)

On the Effect of Local Grain-Boundary Chemistry on the Macroscopic Mechanical Properties of a High Purity Y2O3-Al2O3-Containing Silicon Nitride Ceramic. / Ziegler, A.; McNaney, J.M.; Hoffmann, M. J. et al.
In: Materials Research Society Symposium Proceedings, Vol. 839, P3.14, 11.2004.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review