Stress-enhanced growth rate of alumina scale formed on FeCrAlY alloy

The effect of stresses on the growth rate of alumina scale formed on FeCrAlY alloy is reported. It is found that the compressive growth stress slows the outward diffusion of carbon in the oxide, resulting in enhanced O2− ion transport, thereby accelerating scale growth. The results are confirmed by electrical measurements on the oxidized alloy, which reveal that higher ionic conductivity can be correlated with higher compressive stress. Possible mechanisms of this phenomenon are discussed.