Community Research and Development Information Service - CORDIS

Abstract

During the last decade there has been increasing concern about the fatigue resistance of structural ceramics. In the case of non-transforming monolithic ceramics it appears that damage induced in the wake or at the tip of slowly growing cracks decreases lifetimes under cyclic loads at room temperature, as compared to lifetimes under static loads. Under cyclic mechanical loading at high temperatures, both lower, but also higher lifetimes compared to static loading have been observed. The extent of the latter, so-called positive, fatigue effects is assumed to be closely related to the volume fraction and viscosity of the amorphous grain boundary residues of the sintering additives. In this letter a method to estimate the visco-elastic response of monolithic ceramics to cyclic loading conditions at high temperatures is proposed. A relationship is observed between the visco-elastic energy dissipation measured for two silicon nitride materials, and the structural characteristics of their respective intergranular phases. Some consequences for the fatigue resistance of the tested materials, and of non-transforming monolithic ceramics in general, are discussed.

Additional information

Authors: ROEBBEN G, University of Leuven, Department of Metallurgy and Materials Engineering (BE);VAN DER BIEST O, University of Leuven, Department of Metallurgy and Materials Engineering (BE);STEEN M, JRC Petten (NL)
Bibliographic Reference: Article: Scripta Metallurgica et Materialia, Vol. 33 (1995) No. 3, pp. 1417-1421
Availability: Available from Dr G Roebben, University of Leuven, Department of Metallurgy and Materials Engineering (BE)
Record Number: 199610305 / Last updated on: 1996-03-29
Category: PUBLICATION
Original language: en
Available languages: en
Follow us on: RSS Facebook Twitter YouTube Managed by the EU Publications Office Top