Oxide Spallation in Beta-NiAl Coated Systems under Mechanicalloading
Thermally grown oxide (TGO) spallation increases the degradation rate of aluminide protective coatings during thermomechanical cycling. Thermal expansion misfit between TGO, bond coat and substrate, applied mechanical load in the system, and local instabilities are known triggers for spallation. Mechanical tests have been performed on coated and oxidised AM1 superalloy. In situ and post mortem study including digital image analysis and SEM were performed in order to characterise strain fields and associated damage field. Good correlation is found between oxide strain and damage extent.
Pierre Steinmetz, Ian G. Wright, Alain Galerie, Daniel Monceau and Stéphane Mathieu
M. Harvey et al., "Oxide Spallation in Beta-NiAl Coated Systems under Mechanicalloading ", Materials Science Forum, Vols. 595-598, pp. 101-106, 2008