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Microstructure and High-temperature Oxidation Behavior of Ti3 AlC2/ W Composites.
- Source :
-
Journal of the American Ceramic Society . Feb2013, Vol. 96 Issue 2, p584-591. 8p. 4 Black and White Photographs, 3 Charts, 5 Graphs. - Publication Year :
- 2013
-
Abstract
- Using spark plasma sintering, Ti3 AlC2/ W composites were prepared at 1300°C. They contained 'core-shell' microstructures in which a Ti xW1− x 'shell' surrounded a W 'core', in a Ti3 AlC2 matrix. The composite hardness increased with W addition, and the hardening effect is likely achieved by the Ti x W1− x interfacial layer providing strong bonding between Ti3 AlC2 and W, and by the presence of hard W. Microstructural development during high-temperature oxidation of Ti3 AlC2/ W composites involves α- Al2 O3 and rutile ( TiO2) formation ≥1000°C and Al2 TiO5 formation at ~1400°C while tungsten oxides appear to have volatilized above 800°C. Likely due to exaggerated, secondary grain growth of TiO2-doped alumina and the effect of W addition, fine (<1 μm) Al2 O3 grains formed dense, anisomorphic laths on Ti3 AlC2/5 wt% W surfaces ≥1200°C and coarsened to large (>5 μm), dense, TiO2-doped Al2 O3 clusters on Ti3 AlC2/10 wt% W surfaces ≥1400°C. W potentially affects the oxidation behavior of Ti3 AlC2/ W composites beneficially by causing formation of Ti x W1− x thus altering the defect structure of Ti3 AlC2, resulting in Al having a higher activity and by changing the scale morphology by forming dense Al2 O3 laths in a thinner oxide coating, and detrimentally through release of volatile tungsten oxides generating cavities in the oxide scale. For Ti3 AlC2/5 wt% W oxidation, the former beneficial effects appear to dominate over the latter detrimental effect. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00027820
- Volume :
- 96
- Issue :
- 2
- Database :
- Academic Search Index
- Journal :
- Journal of the American Ceramic Society
- Publication Type :
- Academic Journal
- Accession number :
- 85412135
- Full Text :
- https://doi.org/10.1111/jace.12095