:: Advanced Composites Letters on-line ABSTRACTS ::

Volume 11, Issue 6, 2002

Mechanical behaviour of nickel aluminide reinforced alumina (Al2O3 - NiAl) composites

I. J. Davies^1*, G. Pezzotti², A. Bellosi³, D. Sciti³, and S. Guicciardi³

¹Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia
²Kyoto Institute of Technology, Matsugasaki, Sakyo-Ku, Kyoto 606-8585, Japan
³CNR-IRTEC, via Granarolo 64, 48018, Faenza, Italy

(Received 2/02; accepted 11/02)

*Author to whom correspondence should be addressed

Abstract

The microstructure and mechanical properties of hot-pressed alumina (Al2O3) matrix composites containing 20, 35, or 50 vol% of nickel aluminide (NiAl) were investigated. The mean Al2O3 grain size was found to decrease from approximately 2.0 mm (monolithic Al2O3) to 1.0 mm for the composite containing 50 vol% NiAl. Composite flexural strength values were lower than both the monolithic Al2O3 and NiAl and attributed to the weakly bonded NiAl particles acting as flaw origins. In contrast to this, the fracture toughness increased with NiAl volume fraction to a maximum of 4.90 MPa·m1/2, thus confirming the toughening effect of NiAl addition on Al2O3 ceramics, with the slope of the rising R-curve for the composite being approximately 8 times that of monolithic Al2O3.

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