Influence of grain size on the oxidation behaviour of MA 956

Abstract

The influence of grain size of alloy MA 956 on the oxidation kinetics and scale morphology is investigated at 900 and 1100 °C for up to 1000 h exposure. Specimens with grain sizes of about 3, 150, and 300 μm mean diameter were studied. Grain growth during oxidation was not observed. The results of this work at 1100 °C show that grain size of the alloy does not significantly influence the oxidation kinetics. At 900 °C, however, mass gain values for the small-and medium-grain size material are somewhat lower than those for the large-grain size material, especially for exposures below 100 h. This feature indicates that grain boundaries could have played a role for the supply of Al to the scale. © WILEY-VCH Verlag GmbH, 2001.