Abstract
High-temperature tensile ductility of Al2O3 is much enhanced by spinel (MgO·1.5Al2O3) dispersion. However, the enhanced tensile ductility in Al2O3-20vol%spinel cannot be explained solely from grain size stability or reduction of flow stress. Detailed microstructural analysis reveals that the crack-like cavity growth rate during high-temperature deformation is more sluggish in Al2O3-20vol%spinel than in 0.1wt%MgO-doped single-phase Al2O3. The enhanced tensile ductility in Al2O3-20vol%spinel must be explained from the reduction of crack-like cavity growth rate during deformation. Since the grain boundaries in Al2O3-20vol%spinel mainly consist of Al2O3 grain boundaries and Al2O3/spinel interphase boundaries, the origin of the sluggish crack-like cavity growth in Al2O3-20vol%spinel is due to high resistivity against crack growth in Al2O3/spinel boundaries. Detailed TEM analysis clarifies that there is an epitaxial relationship between Al2O3 and spinel grains in many Al2O3/spinel interphase boundaries. These interphase boundaries are expected to have smaller interfacial energy, which must act to retard the crack-like cavity growth in spinel dispersed Al2O3.
Original language | English |
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Pages (from-to) | 1369-1373 |
Number of pages | 5 |
Journal | Zairyo/Journal of the Society of Materials Science, Japan |
Volume | 46 |
Issue number | 12 |
DOIs | |
Publication status | Published - 1997 |
Keywords
- AlO-spinel
- Crack-like cavity growth
- Interphase boundary
- Superplasticity
- Tensile ductility
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering