Deformation and fracture, during cooling, of the alumina scale developed on Fe3Al

The deformation and fracture, during cooling, of oxide scales developed on Fe3Al has been modelled using finite element analysis (FEA). Embedded defec ts were introduced at the oxide surface and at the oxide/substrate interfac e; the propagation of these defects and the influence of such propagation o n scale spallation was analysed under both elastic and elastic plastic cond itions. Stress relaxation associated with the plastic deformation of the su bstrate delayed scale spallation as indicated by the greater temperature dr op required to cause spallation. In this situation, the presence of the oxi de surface crack influenced scale spallation in a complex manner. The oxide surface crack did not influence the scale spallation process for the linea r elastic analysis, which was solely controlled by the interfacial defect. (C) 2000 Published by Elsevier Science S.A. All rights reserved.