Chapter 36. Processing and Mechanical Properties of Al2O3/Y3Al5O12 (YAG) Eutectic Composite
- John B. Wachtman Jr.
Published Online: 26 MAR 2008
Copyright © 1990 The American Ceramic Society, Inc.
14th Annual Conference on Composites and Advanced Ceramic Materials, Part 2 of 2: Ceramic Engineering and Science Proceedings, Volume 11, Issue 9/10
How to Cite
Mah, T., Parthasarathy, T. A. and Matson, L. E. (2008) Processing and Mechanical Properties of Al2O3/Y3Al5O12 (YAG) Eutectic Composite, in 14th Annual Conference on Composites and Advanced Ceramic Materials, Part 2 of 2: Ceramic Engineering and Science Proceedings, Volume 11, Issue 9/10 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470313053.ch36
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 1990
Print ISBN: 9780470374931
Online ISBN: 9780470313053
A modified Bridgman-type crystal-growing technique was used to fabricate a directionally solidified eutectic composite of Al2O3 and Y3Al5O12 (YAG). The resulting composite did not have a truly directionally solidified microstructure, but the eutectic grains were large, elongated, and aligned with the continuous alumina phase having its a-axis along the solidification direction. This microstructure did not change after heat treatment at 1700°C, 5 h in air. The composite was found to have a flexural (4-pt.) strength of 373 MPa and a fracture toughness (SENB) of 4.3 MPa · m1/2 at room temperature. The strength dropped to 272 MPa at 1375°C and at 1585°C the strength was still 265 MPa. The fracture toughness was retained up to 1585°C. In comparison with sapphire and single-crystal YAG, the composite has a significantly higher fracture toughness at elevated temperatures.