E. A. Fokina

Phase transformations in Ni-Mn-In-based alloys in magnetic field

The effect of a high-strength magnetic field on the phase transformations of ferromagnetic materials based on the Ni-Mn-In system with different degrees of alloying has been revealed experimentally. The effect of the chemical composition of the alloys and magnetic treatment on the martensitic transformations and magnetic transitions has been investigated. It has been established that, upon substituting nickel atoms with manganese atoms, the temperature of the martensitic transformation decreases.

Martensitic and Magnetic Transformations in Ni-Mn-In Alloys

Dilatometry, magnetometry, and optical metallography were used to study structural and magnetic transformations in Ni-Mn-In alloys of different compositions. Temperatures of structural and magnetic transformations of the Ni47 − xMn42 + xIn11 alloys (with x = 0–2) were determined. It is shown that, as the valence electron concentration decreases, the martensitic transformation temperature decreases. Some of the Ni-Mn-In alloys exhibit a ferromagnetic transformation in both the initial austenite and in the arising martensite.

Magnetic-field-induced martensitic transformations in Ni47 − x Mn42 + x In11 alloys (with 0 ≤ x ≤ 2)

Magnetic properties and martensitic transformations in the Ni47 − xMn42 + xIn11 alloys (with 0 ≤ x ≤ 2) have been studied. The magnetic-field-induced martensitic transformation was found to be observed for all the alloys. The critical temperatures of magnetic and structural phase transformations, temperature dependences of spontaneous magnetization of austenite and martensite, and the critical field, at which the martensitic transformation occurs, have been determined based on magnetic measurements performed for the alloys under study. The spontaneous magnetization of the alloys in the martensitic state has been shown to be lower than that in the magnetic-field-induced austenitic state by a factor of six.

Phase transformations and properties of the Ni-Mn-In Heusler alloy

The phase and magnetic transformations in a ferromagnetic alloy of the Ni-Mn-In system are studied using dilatometry, magnetometry, metallography, and scanning electron microscopy. The effect of a magnetic field of varying intensity on the martensitic transformation and magnetic transitions of the Ni47Mn42In11 alloy is found. It is shown that the linear expansion coefficient and magnetization exhibit an anomalous behavior in the region of the magnetostructural transition.

Specific features of the martensitic transformation of deformed austenite in the 50N26 alloy upon cooling and magnetic treatment

The effect of pulsed magnetic field on the martensitic transformation of the austenite stabilized by plastic deformation in the 50N26 alloy, in which the martensite morphology changes under the effect of magnetic field, has been studied. It was established that the austenite stabilization caused by plastic deformation can be completely eliminated by the treatment with magnetic field.

Effect of External Actions and a Magnetic Field on Martensitic Transformation in Steels and Alloys

The historical aspect is provided for research into the effect of a magnetic field and a number of other actions on martensitic transformation in steels and alloys.

On the role of retained austenite in the structure of alloyed steels and the effect of external factors

We present a review of the results of the effect of external factors on the amount of austenite retained in steels and alloys. Possible methods of reducing the amount of retained austenite via the action of cold treatment, magnetic field, and plastic deformation, as well as the question of the effect of retained austenite on the mechanical properties of commercial and model steels and alloys, — have been discussed and analyzed.

Effect of cooling rate on the amount of retained austenite upon bainitic transformations

We have presented a review of the results of investigating the effect of the cooling conditions and heat treatment on the amount of retained austenite and mechanical properties of commercial steels. Possible methods of obtaining enhanced amount of retained austenite due to the stabilization effect, bainitic transformation, and quenching from the intercritical temperature range have been discussed and analyzed.

On the effect of magnetic fields on alloys with isothermal kinetics of martensitic transformation

The effect of magnetic treatment on the isothermal martensitic transformation in the Fe-24% Ni-4% Mn alloy has been investigated. The martensitic transformation in a dc magnetic field at liquid-helium temperature has been analyzed.

Nature of the effect of magnetic fields on the starting temperature of martensitic transformation in iron alloys

The effect of a magnetic field on martensitic transformations, which is satisfactorily described by the Krivoglaz–Sadovskii formula, has been analyzed taking into account the nonequilibrium of the martensitic transformation, the possible adiabatic conditions, and the magnetostriction of the paraprocess in ferromagnetic austenite.