Influence of Cr-content on the local atomic structure of Fe–Cr alloy, a study using EXAFS

Abstract

High Cr ferritic/martensitic steels are considered one of the most promising structural materials for advanced nuclear power plants. Therefore, understanding properties' evolution under operation conditions is of primary importance. Neutron scattering data and more recent ab initio calculations reveal that magnetism controls the transition from the local short-range ordering of the Cr clustering inside the alloy. The transition coincides with the change in the alloy heat of formation, which shifts from a small area with negative values to a region of positive values at around 10% Cr. This work aims to investigate the effect of Cr composition on the local atomic environment of Fe–Cr alloys. This work employed EXAFS to probe the local environment of Fe–Cr alloys as a function of Cr composition. The results show the anomaly (softening) of the nearest neighbor distance around Cr atom in the 10%Cr. Furthermore, the local atomic disorder around Cr absorbing atoms is larger than Fe atoms.