Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. Founded at 2009

Ferromagnetic nanoclusters in austenite: nature, role, characteristics, and controllability

V.N. Pustovoit, Yu.V. Dolgachev

Don State Technical University

DOI: 10.26456/pcascnn/2026.18.XXX

Original article

Abstract: This article examines the nature of magnetic inhomogeneities in austenite steels and their fundamental role in phase transformations. It is shown that austenite, being a paramagnetic phase, contains spontaneously emerging regions of short-range ferromagnetic order (ferromagnetic nanoclusters), the existence of which has been confirmed experimentally using neutron magnetic diffraction methods. The dependence of the magnetic susceptibility of austenite is described by the Langevin function for superparamagnets, which reflects the fluctuation nature of these magnetic inhomogeneities localized in nanometer-sized regions. The magnetic state of the initial phase crucially determines the nature of the γ→α transformation. Using computer simulation based on the Ising model, the effect of an external magnetic field on the characteristics of nanoclusters over a wide temperature range was studied. It has been established that a magnetic field of up to 2,4 MA/m can increase the average cluster size, their total number by two orders of magnitude (most effectively at low temperatures, where the increase reaches 1,4 nm), and increase the proportion of large clusters, as well as extend their stable existence by up to 25%. Experiments with quenching in a constant magnetic field for a range of steels demonstrated a significant reduction in the volume fraction of retained austenite, comparable to cold treatment, and an acceleration of the bainitic transformation kinetics by 1,5-1,8 times. The magnetic field enhances the magnetic heterogeneity of austenite, activates new nucleation centers, and stimulates the multiplicative mechanism of α-phase formation, providing a practical tool for targeted phase transition control during heat treatment of steels in a magnetic field.

Keywords: austenite, magnetic state, nanocluster, steel, hardening, external magnetic field

  • Victor N. Pustovoit – Dr. Sc., Professor, Department of Materials Science and Metal Technologies, Don State Technical University
  • Yuri V. Dolgachev – Dr. Sc., Professor, Department of Materials Science and Metal Technologies, Don State Technical University

For citation:

Pustovoit V.N., Dolgachev Yu.V. Ferromagnitnye nanoklastery v austenite: priroda, rol, kharakteristiki i vozmozhnost upravleniya [Ferromagnetic nanoclusters in austenite: nature, role, characteristics, and controllability], Fiziko-khimicheskie aspekty izucheniya klasterov, nanostruktur i nanomaterialov [Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials], 2026, issue 18, pp. __-__. DOI: 10.26456/pcascnn/2026.18.XXX. ⎘

Full article (in Russian): download PDF file

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