Atom Probe Studies of the Fe–Cr System and Stainless Steels Aged at Intermediate Temperature
Résumé
The a–a9 spinodal decomposition is known to occurr in iron–chromium-based model andindustrial alloys during long-term aging at intermediate temperatures. This decompositioncan be characterized unambiguously by atom probe, and its evolution quantified by meansof various microstructural paramaters directly accessible from concentration profiles. Com-parison with the existing theories of spinodal decomposition will be briefly examined. Thisdecomposition has a direct influence on the material, and can be used to improve magneticor mechanical properties. Conversely, some mechanical properties, such as impact tough-ness, are greatly degradated by this evolution, and can lead to serious problems when, forexample, the integrity of large industrial components is affected. For this reason, extensivework has been carried out to understand the influence of the various alloying elements onthe phase separation and on the embrittlement process. Atom probe contributions in thisarea will be presented in this paper.