Precision Thermal Treatments, Atom Probe Characterization, and Modeling to Describe the Fe-Cr Metastable Miscibility Gap

The Fe-Cr metastable miscibility gap has been studied by high-precision thermal treatments, Vickers micro-hardness (HV) measurements, and atom probe tomography (APT). Thermodynamic modeling further supplements the experimental work. The results obtained show that recent thermodynamic descriptions of the metastable miscibility gap found in literature generally overestimates the consolute temperature. We can show that the source of ambiguity in previous studies is most likely a lack of clear distinction between Cr-Cr clustering and α^ α ′ formation. This distinction is here made by APT results, and it leads to a determined consolute temperature of 580 ± 1 °C for Fe 0.50 Cr 0.50 . The revised thermodynamic modeling of the metastable miscibility gap captures the experimental results and is consistent with the overall picture from the Fe-Cr data in the literature.