High-temperature mechanical behaviour of flaw tolerant alumina-zirconia multilayered ceramics

The mechanical behaviour of alumina-zirconia multilayered ceramics designed with thin internal compressive layers has been investigated under flexural loading at room and high temperature. Young's modulus and the sintering evolution of each layer have been experimentally determined up to 1200 degrees C, to account for the residual stress distribution in the layered composite. The fracture behaviour has been assessed by indentation-strength experiments at different temperatures and by a fracture mechanics analysis. Experimental findings showed that improvement in mechanical properties of the laminate at high temperatures in comparison to the alumina-based monolithic material was essentially related to the distinct modes of failure observed as a function of the temperature, in the presence of energy release mechanisms such as crack bifurcation and/or delamination that may be used as a tool for designing tolerant materials at high temperatures. (c) 2007 Published by Elsevier Ltd on behalf of Acta Materialia Inc.