Features of Martensitic Transformation in Steel during Quenching in a Constant Magnetic Field

2019 ◽  
Vol 946 ◽  
pp. 304-308 ◽  
Author(s):  
Viktor N. Pustovoit ◽  
Yuri V. Dolgachev ◽  
L.P. Aref'eva
Keyword(s):  
Magnetic Field ◽  
Martensitic Transformation ◽  
External Magnetic Field ◽  
Constant Magnetic Field ◽  
Electric Resistivity ◽  
Nucleation Center ◽  
Martensite Formation ◽  
Resistivity Method ◽  
Elastic Forces ◽  
Energy Of Formation

The data on the occurrence of martensitic transformation in steel under the action of a magnetic field were obtained by the electric resistivity method. The obtained data indicate the possibility of stress-assisted martensite formation in the temperature range of Ms-Md (in which superplasticity of austenite is observed). This possibility is due to the magnetic heterogeneity of austenite. Nanosized regions with a ferromagnetic order are present in the paramagnetic matrix. They can perceive the energy of the external magnetic field through the magnetostrictive stresses and change the fields of the elastic forces in the crystal lattice. All this leads to a decrease in the energy of formation of the nucleation center.

scholarly journals High Frequency Magnetoimpedance of FeNi/Cu/FeNi Sensitive Elements with Different Geometries

2009 ◽  
Vol 152-153 ◽  
pp. 373-376 ◽  
Author(s):  
Stanislav O. Volchkov ◽  
Andrey V. Svalov ◽  
G.V. Kurlyandskaya
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
External Magnetic Field ◽  
Finite Elements ◽  
Magnetic Anisotropy ◽  
Constant Magnetic Field ◽  
High Frequency ◽  
Complex Impedance ◽  
Rf Sputtering ◽  
Frequency Range

In this work magnetoimpedance (MI) behaviour was studied experimentally for Fe19Ni81(175 nm)/Cu(350 nm)/Fe19Ni81(175 nm) sensitive elements deposited by rf-sputtering. A constant magnetic field was applied in plane of the sandwiches during deposition perpendicular to the Cu-lead in order to induce a magnetic anisotropy. Sandwiches with different width (w) of FeNi parts were obtained. The complex impedance was measured as a function of the external magnetic field for a frequency range of 1 MHz to 700 MHz for MI elements with different geometries. Some of MI experimental data are comparatively analysed with finite elements numerical calculations data. The obtained results can be useful for optimization of the design of miniaturized MI detectors.

Changes in the Structure of Steel during Quenching in a Magnetic Field

2020 ◽  
Vol 989 ◽  
pp. 79-84 ◽  
Author(s):  
Viktor N. Pustovoit ◽  
Yuri V. Dolgachev ◽  
L.P. Aref'eva
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Martensitic Transformation ◽  
Specific Surface ◽  
Surface Area ◽  
Constant Magnetic Field ◽  
Surface Relief ◽  
Volumetric Strain ◽  
Transformation Products ◽  
Electron Microscopes

The structure of martensite obtained by quenching steel under the action of a constant magnetic field was studied. The kinetic changes of the martensitic transformation, caused by the action of a magnetic field, are expressed in the structure by an increase in the dispersity of the transformation products. Samples of steels C45, 100CrMn6 and 30HGSA were investigated. Dispersity was evaluated statistically in images obtained on light and electron microscopes. The specific surface area was measured and the parameters of the surface relief caused by martensitic transformation were studied. Experimental data show that after quenching in a magnetic field, a decrease in the volumetric strain of the transformation, an increase in the dispersity of packets of martensitic crystals and components of the packets are observed. It is concluded that an increase in dispersion and a fragmentation of the structure of martensite are mainly the result of multiplicative nucleation.

The Formation Energy of Martensite Nuclei and the Phase Transition Kinetics under the Action of an External Magnetic Field

2021 ◽  
Vol 410 ◽  
pp. 3-8
Author(s):  
Viktor N. Pustovoit ◽  
Yuri V. Dolgachev
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Initial Phase ◽  
Formation Energy ◽  
Martensite Phase ◽  
Nucleation Center ◽  
Austenite Matrix ◽  
Ferromagnetic Order ◽  
The Matrix ◽  
Phase Transition Kinetics

The formation energy of martensite nuclei in the austenite matrix is calculated. Nanoclusters with ferromagnetic order, which exist in austenite above the Curie temperature, reduce the formation energy of a critical martensite nucleation center when exposed to an external magnetic field. The data obtained are explained by the magnetic separation of the initial phase under the action of a magnetic field. A fluctuation increase in nanovolumes with a ferromagnetic order in austenite increases the energy in a atoms group of the matrix phase with a parallel spins arrangement. As a result, the nucleation rate of the martensite phase increases and the martensitic transformation proceeds more completely.

scholarly journals Magnetoresistance and Thermal Transformation Arrest in Pd2Mn1.4Sn0.6 Heusler Alloys

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2308 ◽  
Author(s):  
Xiao Xu ◽  
Hironari Okada ◽  
Yusuke Chieda ◽  
Naoki Aizawa ◽  
Daiki Takase ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Martensitic Transformation ◽  
Curie Temperature ◽  
Field Dependence ◽  
Magnetic Field Dependence ◽  
Thermal Transformation ◽  
Heusler Alloys ◽  
Parent Phase ◽  
Electric Resistivity ◽  
Transformation Temperatures

The magnetization, electric resistivity, and magnetoresistance properties of Pd 2 Mn 1 . 4 Sn 0 . 6 Heusler alloys were investigated. The Curie temperature of the parent phase, martensitic transformation temperatures, and magnetic field dependence of the martensitic transformation temperatures were determined. The magnetoresistance was investigated from 10 to 290 K, revealing both intrinsic and extrinsic magnetoresistance properties for this alloy. A maximum of about − 3 . 5 % of intrinsic magnetoresistance under 90 kOe and of about − 30 % of extrinsic magnetoresistance under 180 kOe were obtained. Moreover, the thermal transformation arrest phenomenon was confirmed in the Pd 2 Mn 1 . 4 Sn 0 . 6 alloy, and an abnormal heating-induced martensitic transformation (HIMT) behavior was observed.

Effects of High Magnetic Field and Tensile Stress on Martensitic Transformation Behavior and Microstructure At 4 K in Fe-Ni-C Alloys

1995 ◽  
Vol 398 ◽  
Author(s):  
H. Ohtsuka ◽  
K. Nagai ◽  
S. Kajiwara ◽  
H. Kitaguchi ◽  
M. Uehara
Keyword(s):  
Magnetic Field ◽  
Martensitic Transformation ◽  
Tensile Stress ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
High Magnetic Field ◽  
Constant Magnetic Field ◽  
Critical Magnetic Field ◽  
Transformation Behavior ◽  
The Magnetic Field

ABSTRACTEffects of high magnetic field and tensile stress on martensitic transformation behavior and microstructure at 4 K have been studied in Fe-31Ni-0.4C and Fe-27Ni-0.8C shape memory alloys. It was found that the critical magnetic field to induce martensitic transformation is between 7.5 T and 10 T. In the case of Fe-27Ni-0.8C, martensitic transformation is stress-induced at lower level of stress in magnetic field than in the case when no magnetic Field is applied. The amount of martensite formed by increasing the magnetic field under constant stress is larger than that formed by increasing the stress in the constant magnetic field.

scholarly journals Propagators of charged particles in an external magnetic field, expanded over Landau levels

2015 ◽  
Vol 30 (24) ◽  
pp. 1550140 ◽  
Author(s):  
A. V. Kuznetsov ◽  
A. A. Okrugin ◽  
A. M. Shitova
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Fields ◽  
Standard Model ◽  
Constant Magnetic Field ◽  
Charged Particles ◽  
Landau Levels ◽  
The Standard Model ◽  
First Time

Various forms of expressions for the propagators of charged particles in a constant magnetic field that should be used for investigations of electroweak processes in an external uniform magnetic fields are discussed. Formulas for the propagators of the Standard Model charged [Formula: see text]- and scalar [Formula: see text]-bosons in an arbitrary [Formula: see text]-gauge, expanded over Landau levels, are derived for the first time.

scholarly journals Viability of old house borer (Hylotrupes bajulus) larvae exposed to a constant magnetic field of 98 mT under laboratory conditions

2009 ◽  
Vol 61 (1) ◽  
pp. 129-134 ◽  
Author(s):  
Snezana Raus ◽  
Dajana Todorovic ◽  
Z. Prolic
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Constant Magnetic Field ◽  
Control Group ◽  
Laboratory Conditions ◽  
Neurohumoral Regulation ◽  
Hylotrupes Bajulus ◽  
Mass Increase

The purpose of our experiment was to establish how exposure to a constant magnetic field of 98 mT affects behavior in terms of viability and larval mass of the old house borer (Hylotrupes bajulus L.). It is demonstrated that larvae exposed to this magnetic field show statistically significant higher viability, as well as a tendency of mass increase in comparison with the control group. These results can be attributed to the modulatory effect of the employed external magnetic field on metabolism and neurohumoral regulation in the insects.

Photovoltaic Generator Based on Laser-Induced Reversible Aggregation of Magnetic Nanoparticles

2020 ◽  
Vol 75 (2) ◽  
pp. 171-173 ◽  
Author(s):  
Melánia Babincová ◽  
Peter Babinec
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticles ◽  
External Magnetic Field ◽  
Constant Magnetic Field ◽  
Periodic Motion ◽  
Electromotive Force ◽  
Cluster Formation ◽  
Force Generation ◽  
Reversible Aggregation ◽  
Faraday Law

AbstractA new principle of electromotive force generation is proposed, based on the intermittent laser-induced reversible cluster formation due to the aggregation of magnetic nanoparticles in a ferrofluid placed in the constant magnetic field. In such a configuration, according to Faraday law, in response to unsteady light-induced periodic motion of magnetized materials in an external magnetic field, an alternating current is induced in the coil wrapped around the ferrofluid tube.

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