Abstract
This paper presents the results of a Mössbauer spectroscopy investigation of the processes in the binary alloys Fe100−cCrc (c, at. % = 6.0, 9.4, 13.2) and of the short-range (SR) atomic ordering accelerated by applying warm severe plastic deformation via high pressure torsion (HPT). After warm HPT treatment, in the vicinity of the concentration c = 9 at. %, there was revealed to be an inversion of the sign of the SR order, the anomaly of the formation of a Fe–Cr solid solution, which was predicted ab initio and is observed at long-term anneals and exposures to irradiation by electrons. The acceleration of the SR ordering at HPT is due to the continuous generation and a large number density of mobile point defects.
Highlights
Iron-rich Fe–Cr alloys are the base of conventional stainless steels, which are widely used in industry, including the nuclear industry, owing to their excellent mechanical and chemical properties and high resistance to void swelling [1,2,3]
Using methods of Mössbauer spectroscopy, in the binary alloys Fe100−c Crc (c, at. % = 6.0, 9.4, 13.2), we have investigated the processes of SR ordering at warm (573 K) severe plastic deformation in the rotating Bridgman anvils
The concentration anomaly of the change in the SR atomic order from the SRO type to the SRC type in the course of increasing Cr concentration is explained with the help of the existent specificity of the ferromagnetic state of the Fe matrix, namely, by the magnetic frustration [12,13,14], a phenomenon that leads to avoiding the occurrence of Cr atoms on the nearest-neighbor shell
Summary
Iron-rich Fe–Cr alloys are the base of conventional stainless steels, which are widely used in industry, including the nuclear industry, owing to their excellent mechanical and chemical properties and high resistance to void swelling [1,2,3]. Fe–Cr solid solution, the oversaturated high-chromium alloys and steels demonstrate a tendency to phase separation into Fe-rich (α-phase) and Cr-rich (α0 -phase) fractions leading to the embrittlement found first upon ageing at 475 ◦ C and named as 475 ◦ C embrittlement. It is known [9,10,11,12,13,14] that an inversion in the type of short-range (SR) order formation takes place around 9–10 at. It is known [9,10,11,12,13,14] that an inversion in the type of short-range (SR) order formation takes place around 9–10 at. % Cr in the limits: from SR ordering, i.e., a tendency of atoms of different kinds neighbouring each other, to SR clustering, i.e., the opposite tendency of atoms of the same kind to neighbour each other
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