Microstructural constraints for creep in SiC-whisker-reinforced Al{sub 2}O{sub 3}
- Univ. de Sevilla (Spain). Dept. de Fisica de la Materia Condensada
- Argonne National Lab., IL (United States). Energy Technology Div.
New and published creep data obtained on a SiC-whisker-reinforced Al{sub 2}O{sub 3} composite have been analyzed in terms of an effective grain size and a threshold/critical stress. These concepts allow the formation of a consistent picture of the high-temperature deformation of these composites. For low volume fractions of whiskers, before the formation of a point-contact percolative limit is reached, deformation proceeds via grain-boundary sliding after the applied stress exceeds a temperature-dependent threshold stress. In this regime, the nominal grain size is the most important microstructural feature. For larger volume fractions of whiskers, up to the critical volume fraction for formation of facet-to-facet contact, whiskers inhibit grain-boundary sliding and deformation proceeds by means of pure diffusion. In this regime, the most important microstructural feature is an effective grain size, i.e. the spacing between the whiskers. Deformation proceeds until the stress reaches a temperature-dependent critical stress. At this point, damage occurs by unaccommodated grain-boundary sliding and creep is no longer in a steady state.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL
- Sponsoring Organization:
- USDOE, Washington, DC (United States); Comision Interministerial de Ciencia y Tecnologia (Spain)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 302363
- Journal Information:
- Acta Materialia, Journal Name: Acta Materialia Journal Issue: 18 Vol. 46; ISSN 1359-6454; ISSN ACMAFD
- Country of Publication:
- United States
- Language:
- English
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