Distribution of Cr atoms in the surface zone of Fe-rich Fe–Cr alloys quenched into various media: Mössbauer spectroscopic study

Cr Segregation and Impact Fracture in a Martensitic Stainless Steel

“…In fact, the internal part of Charpy probes undergoes a slower cooling which allows a longer diffusion path of C and Cr atoms. Several experimental [15,[18][19][20][21] and simulation [15,20] works give clear evidence of the clustering tendency in Fe-Cr alloys which decreases as temperature increases, however MS measurements [5] and Monte Carlo simulations [24] showed that some Cr atoms aggregation occurs also in austenitic field, in particular C-Cr associates [22,26] act as preferred sites for the clustering of Cr atoms. It is evident that higher RW values involve favorable conditions for Cr atoms aggregation.…”

“…In fact, the internal part of Charpy probes undergoes a slower cooling which allows a longer diffusion path of C and Cr atoms. Several experimental [15,[18][19][20][21] and simulation [15,20] works give clear evidence of the clustering tendency in Fe-Cr alloys which decreases as temperature increases, however MS otherwise it would be detected also on the polished surface of the probes but only on a microscopic scale.…”

“…Segregation, precipitation, and phase separation in Fe-Cr systems have been analyzed by Kuronen et al [15], showing that the precipitation of Cr occurs into isolated pockets in bulk Fe-Cr alloys with Cr content higher than 10 at.%. Mirebeau et al [16] and Dubiel et al [17][18][19][20] evidenced that short range order (SRO) develops in Fe-Cr alloys following prolonged heat treatments up to ~630 • C with a clustering tendency. To explain the corrosion behavior of Fe-Cr alloys Liu et al [21] considered the effect of SRO on establishing a percolation network of Cr atoms.…”

The Effect of Short-Range Order on Passivation of Fe-Cr Alloys

“…A series of these samples (here termed random solid solution, "RSS") were water quenched from 800 • C. In order to obtain short-ranged ordered, "SRO" samples, following the 800 • C, 24 hour treatment, the temperature was lowered to 520 • C for 24 hours (FeCr 17.4) or 430 • C (FeCr 9.1, FeCr 11.6, FeCr 14.4) for 96 hours, following the protocols used in the neutron diffraction 25 and Mössbauer studies. [26][27][28] These samples were not abraded or polished prior to electrochemical testing following these heat treatments since such a procedure would destroy the SRO in the surface of the samples.…”

“…These first-principles based calculations predicting the inversion in H mix have experimental verification from both neutron scattering 25 and Mössbauer spectroscopy studies. [26][27][28] The neutron scattering experiments examined the Cowley-Warren short-range order (SRO) parameter as a function of Cr composition in polycrystalline Fe p Cr 1-p alloys for 0 < 1-p < 0.15. Samples were homogenized at 800 • C and then heated in an evacuated quartz tube at 520 • C to reach an equilibrium SRO state.…”