Chapter 75. Erosion and Strength Degradation of an Elastic Modulus Graded Alumina-Glass Composite
- Todd Jessen and
- Ersan Ustundag
Published Online: 26 MAR 2008
Copyright © 2000 The American Ceramic Society
24th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 21, Issue 3
How to Cite
Panat, R. P., Jakus, K. and Ritter, J. E. (2000) Erosion and Strength Degradation of an Elastic Modulus Graded Alumina-Glass Composite, in 24th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 21, Issue 3 (eds T. Jessen and E. Ustundag), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294628.ch75
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 2000
Print ISBN: 9780470375686
Online ISBN: 9780470294628
- AI composites;
- mechanical properties;
- microstructural analysis;
- flexural strength
Previous research has shown that Hertzian cone cracking is suppressed in ceramic composites whose elastic modulus increases with depth below the surface. The objective of this research was to determine if these modulus-graded composites would also exhibit superior resistance to particle impact damage. Therefore, impact damage with sharp and blunt particles was studied in monolithic and modulus-graded glassy alumina. The composite was fabricated by impregnating a dense, fine-grained alumina with an aluminosilicate glass having a lower elastic modulus than the alumina. This produced a functionally gradient composite with decreasing glass content below the surface, thus causing the elastic modulus to monotonically increase with depth. The aluminosilicate glass had a coefficient of thermal expansion and Poisson ratio the same as the alumina. Therefore, the composite had no macroscopic, long-range residual stresses.
The sharp multi-particle impact (erosion) experiments were conducted with a slinger type apparatus. The blunt single impact experiments were conducted with small stainless steel balls using a particle accelerator gas-gun. In the case of the sharp particle impact experiments, erosive wear and strength degradation was measured as a function of depth below the surface. For the single impact experiments, the onset of ring cracking was determined and compared to that for monolithic alumina. These experiments were designed to give an insight into the effect of the alumina-glass microstructure and the corresponding elastic modulus gradient on the particle impact damage resistance of this composite.
It was found that the modulus-graded alumina exhibited the same erosive wear, post erosion strength, and ring crack formation, as did the monolithic alumina.