On grain boundary strength in sintered A12O3
- 1 May 1985
- journal article
- research article
- Published by Taylor & Francis in Philosophical Magazine A
- Vol. 51 (5) , 765-776
- https://doi.org/10.1080/01418618508245286
Abstract
Scanning and transmission electron microscopy and the C-Pt replica technique have been used to investigate grain boundary structures in sintered polycrystalline A12O3 with varying concentrations of MgO dopant. A method is proposed for evaluating the fracture toughness, Kβb c, and the strength of grain boundaries from the percentage of intergranular fracture as observed along the path of a propagating macrocrack. The resulting Kβb c is found to be between 0·1 and 0·4 of the value characterizing the fracture toughness of the A12O3 lattice, the observed grain boundary strengths being 400–1300 MPa. A comparison of various alumina structures of different grain boundary strengths but similar microcrack densities and fracture properties indicates that for microscopic fracture processes the distribution of flaw sites is more important than the grain boundary strength.Keywords
This publication has 15 references indexed in Scilit:
- Toughening of Ceramics by Circumferential MicrocrackingJournal of the American Ceramic Society, 1981
- Increased fracture toughness of ceramics by energy-dissipative mechanismsJournal of Materials Science, 1981
- Stress‐Induced Microcracking at Second‐Phase InclusionsJournal of the American Ceramic Society, 1981
- Alumina structure with improved fracture propertiesPhysica Status Solidi (a), 1981
- Microfracture in brittle solids resulting from anisotropic shape changesActa Metallurgica, 1980
- A Treatment of Inelastic Deformation Around a Crack Tip due to MicrocrackingJournal of the American Ceramic Society, 1980
- Grain-size dependence of microcrack initiation in brittle materialsJournal of Materials Science, 1980
- Microfracture from thermal expansion anisotropy—I. Single phase systemsActa Metallurgica, 1978
- Fracture‐Strength Anisotropy of SapphireJournal of the American Ceramic Society, 1976
- Crack Propagation Method for Measuring Grain Boundary Energies in Brittle MaterialsJournal of the American Ceramic Society, 1966