Effect of grain size on the oxidation of Fe–13Cr–5Ni alloy at 973 K in Ar–21 vol%O2.

Effect of grain refinement from 370 to 34 μm on oxidation of transition Fe–13Cr–5Ni alloy at 973 K in Ar–21 vol%O 2 was investigated. The measured weight gains were fitted taking into account a mixed kinetic model with an initial linear and subsequent parabolic growth behaviour. Different scale microstructural evolution was discussed. Contribution of grain refinement to the oxidation is predominantly due to its effect on the inward oxidation process. Decreasing grain size promoted intergranular oxidation, accelerated formation of the Cr-containing inner scale, contributed to the faster transition to the steady state oxidation and correspondingly slightly improved the oxidation resistance. [ABSTRACT FROM AUTHOR]