Interaction of oxide layers with dislocations for an austenitic stainless steel

The interaction between dislocations and an oxide layer has been studied for a stainless steel. In spite of the low temperature, the oxide layer formed at 600°C during 100 h is composed of (Fe,Cr)2O3, with composition depending on the pre-existing dislocation structure, while a slight Cr depletion is observed in the alloy. After oxidation, the dislocation configurations are modified over a few hundreds of nanometers depending on the initial microstructure. In samples oxidized before mechanical cycling, marked modifications of the plasticity in the near surface layers are observed. In both cases, the diffusion of Cr atoms and the associated vacancy flux are responsible for the dislocation configuration modifications.