Intermetalllic phase formations during processing of this type of steel are contributing to embrittlement of the material, thus we are searching for strategies to decelerate their nucleation and growth.
By using microanalysis with FEG-SEM, we found two temperature-dependent formation types of the s-phase, where the rim-like formation (in contrast to lamellar pseudo-eutectoid formation in alternation with newly formed austenite) is observed above 950°C in this steel grade. Elemental profiles in the lower part of the picture, as determined by EPMA analysis, show the change of Mo-content across the s-phase / austenite interface.
We are interested to understand, by interpreting different element profiles, the respective role of diffusion at this grain boundary and the grain boundary mobility (the question of „moving boundary“) for the evolution of the intermetallic phase.