Grain Size Effects on the Oxidation of Fe-33Ni-19Cr Alloy at 700°C

Abstract

The effect of different grain size on the oxidation of Fe-33Ni-19Cr alloy was discussed. The present paper focuses on the oxidation behaviour in dry air at temperature of 700oC with respect to oxidation kinetics. Solution treatment was applied to Fe-33Ni-19Cr alloy by means of different solution annealing temperature to alter the average grain size of the specimens. Solution heat treatments were carried out on Fe-Ni-Cr alloys at three different temperatures, namely, 1000oC, 1100oC and 1200oC. The results showed that the average grain size increased with increase in solution annealing temperature that was significantly affecting the oxidation kinetic of the materials. Optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) were employed in this study to analyse the oxidation behaviour of solution-annealed samples. Smaller grain size improves the protective oxidation behaviour by enhancing spallation resistance and reducing oxidation rate. Spallation resistance correlates with a reduction in texture of the oxide layers.