Measurement and analysis of buckling and buckle propagation in compressed oxide layers on superalloy substrates

The mechanisms whereby thin thermally grown aluminum oxide layers detach from superalloy/ bond coat substrates have been investigated. Experimental studies have been based on the use of applied compressions that superpose on the residual compression and activate the failure mechanisms. These studies have revealed a sequence comprising buckling, buckle propagation and spalling. The observations have been analyzed using the established decohesion mechanics of compressed films. Consistency between the measurements and the mechanics has been established. enabling the interface adhesion parameters to be ascertained. The results suggest a relatively weak interface, with adhesions typical of those found for metal/oxide interfaces subject to weakening by segregation. (C) 1998 Acta Metallurgica Inc. Published by Elsevier Science ltd. All rights reserved.