High temperature oxidation of Ni-20Cr alloy under compressive stress

The effect of compressive stress on the oxidation kinetics and the revolution of the surface morphology formed on Ni-20Cr alloy was investigated at 900 °C. The study was carried out mainly by comparisons of surface morphology of oxidized samples observed by scanning electronic microscopy. And the oxidation kinetics curves were assessed by two kinds of thermalgravimetric methods. The results indicate that applying the compressive stress induced an increase in the oxidation rate when the applied stress lowered 5MPa. Failure of the oxide scales is depended on the stress level, exceeding 5MPa the oxide scales began to crack and even spall. (paper)