Toughening Behavior in Ceramics and Cermets
Journal
Key Engineering Materials
Journal Volume
161-163
Pages
285-290
Date Issued
1999
Author(s)
Abstract
The development of high strength (? 1 GPa), high toughness (? 10 MPa¡Ôm) ceramic systems is being examined using two approaches. In silicon nitride, toughening is achieved by the introduction of large prismatic shaped grains dispersed in a fine grain matrix. For the system examined herein, both the microstructure and the composition must be controlled. A distinctly bimodal distribution of grain diameters combined with controlled yttria to alumina ratio in additives to promote interfacial debonding is required. Using a cermet approach, ductile Ni3Al-bonded TiC exhibited toughening due to plastic deformation within the Ni3Al binder phase assisted by interfacial debonding and cleavage of TiC grains. The TiC-Ni3Al cermets have toughness values equal to those of the WC-Co cermets. Furthermore, the TiC-Ni3Al cermets exhibit high strengths that are retained in air to temperatures of ? 1000¢XC.
Subjects
Carbide
Nickel Aluminide-Bonded
Self-Reinforced
Silicon Nitride
Strength
Toughness
Type
journal article