ANALYSIS ON FAILURES OF PROTECTIVE-OXIDE LAYERS AND CYCLIC OXIDATION

A condition of oxide-scale spalling is derived from the concept of str ain energy proposed by Evans. By considering the probabilistic distrib ution of fracture strain energy across the metal oxide interface, the fraction of oxide scale spalled is described as a function of the weig ht of oxide before cooling and temperature change. The cyclic-oxidatio n behavior is modeled with this result. The prediction by the model is shown to be in good agreement with data on the oxidation behavior und er thermal cycling.