Influence of grain size on the oxidation behavior of NbCr2 alloys at 950–1200 °C

The oxidation behavior of mechanically alloyed microcrystalline NbCr2 intermetallics was investigated at 950–1200 °C in air by SEM in comparison with coarse-grain cast alloys. Results indicate that the mechanically alloyed alloys possess a better oxidation resistance and are less permeable to nitrogen than the cast alloys. At 1200 °C, the mechanically alloyed NbCr2 alloys show a better resistance to scale spallation than the cast materials. The differences observed above are attributed to the finer grains increasing the relaxation of the oxide scale stress and improving the adhesion of the oxide layer on the matrix.