The tensile straining of oxidized Fe‐Cr‐Al‐Y alloys

Abstract

Abstract The apparent tensile fracture strains, at which cracking of α‐Al 2 O 3 scales formed on Fe‐Cr‐Al‐Y alloys during oxidation in 1 atm oxygen at 1200 °C occur, have been determined by two methods at room temperature. The values are reproducible and depend on the oxidation time but are within the range 1.4% to 2.3%. These are significantly higher than other published values for thermally formed oxides. It has also been observed that an intermediate thermal cycle to room temperature during the oxidation period does not affect significantly the subsequently measured fracture strain. These relatively high values are discussed in terms of two tentative hypotheses, one relating to flaws in the oxide, the other to possible loss of cohesion of oxide which is too fine to be detected by the methods used.