Papers by Keyword: Interface Segregation

Abstract: The paper presents the results of microstructure evolution studies of hard magnetic FeCr22Co15 alloy, destructed by tension and torsion at 800 and 850°C. The temperatures and deformation rates corresponded to the condition of superplasticity of Fe-Cr-Co alloys. Observations of longitudinal section of deformed samples in scanning electron microscope showed a formation of weak gradient microstructure with highest grain refinement in the surface layer of material. Precipitation of intermetallic σ-phase was also observed, with its maximum amount in zones of the highest deformation.

Abstract: Atomic-scale interface segregation behaviour of Nb and Mo during different stages of recrystallisation of a-Fe has been investigated using a three-dimensional atom probe (3DAP). Experimental procedures to analyse a specific region of interest in the specimens and to determine an orientation relationship between analysed contiguous grains are briefly described, and then analytical artefacts which may affect the measured solute distribution are discussed. Atom probe analysis reveals that Gibbs free energy of segregation of Nb is larger than that of Mo in a-Fe, implying that a stronger solute Nb-interface interaction can be a reason for the larger retardation effect of recrystallisation by Nb addition. The comparison of measured solute profiles at migrating recrystallisation interfaces with calculated solute profiles show that Cahn’s solute drag model gives a reasonable fit to solute profiles for migrating interfaces.