Structural phase transformations during deformation Of Fe-Co-V alloys using the high-pressure torsion method

Fe-Co alloys belong to the soft magnetic materials and have an extremely high value of saturation magnetization σ at room temperature. In particular, Fe-Co alloy with the equiatomic ratio of components at room temperature has the maximal σ value among all known ferromagnetic materials. Unfortunately, it is hard to reproduce the unique magnetic properties of these alloys (especially Fe-Co alloys) due to their high fragility caused mainly by the formation of far atomic ordering according to B2 type in the structure. Adding vanadium to the Fe-Co alloys increases plasticity, but it reduces basic magnetic characteristics. In this paper, using the X-ray structural analysis, transmission scanning microscopy, and magnetometry, the authors analyzed the influence of high-pressure torsion at the temperatures of 77 and 295 K on the structure and phase composition of soft magnetic alloys (Fe-Co)100-xVx (x=0–6.0). As the principal structural parameter before and after deformation, the authors analyzed the magnitude of γ-phase volume ratio in the BCC magnetic matrix. The study identified that plastic deformation causes the suppression of formation of excessive γ-phase in alloys containing (3.0–6.0) % V. The study shows that the loss of γ-phase is observed with the increase of high-pressure torsion deformation firstly in the alloys with the high vanadium proportion and at the deformation effect at higher temperature (295 K). The authors conclude that the detected effect is a consequence of γ→α martensite transformation caused by deformation by analogy to TRIP-effect. The study identified that the suppression of paramagnetic γ-phase leads to a noticeable increase in the specific saturation magnetization.

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GRAIN REFINEMENT AND MICROSTRUCTURE EVOLUTION IN ALUMINUM A2618 ALLOY BY HIGH-PRESSURE TORSION

Jurnal Teknologi ◽

10.11113/jt.v78.9163 ◽

2016 ◽

Vol 78 (6-9) ◽

Author(s):

Intan Fadhlina Mohamed ◽

Seungwon Lee ◽

Kaveh Edalati ◽

Zenji Horita ◽

Shahrum Abdullah ◽

...

Keyword(s):

Plastic Deformation ◽

High Pressure ◽

Grain Refinement ◽

Room Temperature ◽

Rotation Speed ◽

High Pressure Torsion ◽

Applied Pressure ◽

Saturation Level ◽

Microstructural Refinement ◽

Average Grain Size

This work presents a study related to the grain refinement of an aluminum A2618 alloy achieved by High-Pressure Torsion (HPT) known as a process of Severe Plastic Deformation (SPD). The HPT is conducted on disks of the alloy under an applied pressure of 6 GPa for 1 and 5 turns with a rotation speed of 1 rpm at room temperature. The HPT processing leads to microstructural refinement with an average grain size of ~250 nm at a saturation level after 5 turns. Gradual increases in hardness are observed from the beginning of straining up to a saturation level. This study thus suggests that hardening due to grain refinement is attained by the HPT processing of the A2618 alloy at room temperature.

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Influence of Annealing Temperature on the Crystallization Kinetics of Fe82Si8B10 Amorphous Ribbon

Journal of Engineering Science ◽

10.3329/jes.v11i1.49553 ◽

2020 ◽

Vol 11 (1) ◽

pp. 107-112

Author(s):

A Said Sikder ◽

SD Nath ◽

SS Sikder

Keyword(s):

Crystallization Kinetics ◽

Room Temperature ◽

Annealing Temperature ◽

Amorphous Ribbon ◽

Primary Crystallization ◽

Soft Magnetic Materials ◽

Power Transformers ◽

Soft Magnetic ◽

Potential Applications ◽

Kinetics Of

Amorphous soft magnetic materials have significant potential applications in specialist power transformers and in inductive devices. With the composition of Fe82Si8B10, 82% of the transition metals Fe and about 18% of metalloid or glass-former elements like B and Si are strongly magnetic at room temperature and offer dynamic opportunities for engineering applications. The crystallization kinetics has been studied by differential thermal analysis (DTA). The sample was annealed in a controlled way in the temperature range of 350-450°C at constant annealing time one hour. The kinetics of primary crystallization α-Fe(Si) phase and secondary crystallization Fe2B phase was studied as affected due to temperature. The sample annealed at 350oC temperature is almost unchanged which is still lower than that of primary crystallization temperature but the same condition when sample annealed at 450°C completely shows that the primary crystallization α-Fe(Si) phase has vanished and crystallization event took place to a good extent. Journal of Engineering Science 11(1), 2020, 107-112

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Effect of the electrodeposition potential on the magnetic properties of FeCoNi films

Materials Science-Poland ◽

10.2478/msp-2019-0044 ◽

2019 ◽

Vol 37 (3) ◽

pp. 389-394

Author(s):

Setia Budi ◽

Sukro Muhab ◽

Agung Purwanto ◽

Budhy Kurniawan ◽

Azwar Manaf

Keyword(s):

Magnetic Properties ◽

Saturation Magnetization ◽

Sulfate Solution ◽

Synthesis Process ◽

Magnetic Characteristics ◽

Soft Magnetic ◽

X Ray ◽

Ni Content ◽

The Mean ◽

Feconi Alloy

AbstractThe effect of electrodeposition potential on the magnetic properties of the FeCoNi films has been reported in this paper. The FeCoNi electrodeposition was carried out from sulfate solution using potentiostatic technique. The obtained FeCoNi films were characterized by X-ray diffractometer (XRD), atomic absorption spectrometer (AAS) and vibrating sample magnetometer (VSM). It has been shown that the electrodeposition potential applied during the synthesis process determines the magnetic characteristics of FeCoNi films. The more negative potential is applied, the higher Ni content is in the FeCoNi alloy. At the same time, Co and Fe showed almost similar trend in which the content decreased with an increase in applied potential. The mean crystallite size of FeCoNi films was ranging from 11 nm to 15 nm. VSM evaluation indicated that the FeCoNi film is a ferromagnetic alloy with magnetic anisotropy. The high saturation magnetization of FeCoNi film was ranging from 86 A·m2/kg to 105 A·m2/kg. The film is a soft magnetic material which was revealed by a very low coercivity value in the range of 1.3 kA/m to 3.7 kA/m. Both the saturation magnetization and coercivity values decreased at a more negative electrodeposition potential.

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Diffusive and displacive phase transitions in Ti–Fe and Ti–Co alloys under high pressure torsion

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2017.11.317 ◽

2018 ◽

Vol 735 ◽

pp. 2281-2286 ◽

Cited By ~ 17

Author(s):

B.B. Straumal ◽

A.R. Kilmametov ◽

Yu. Ivanisenko ◽

A.A. Mazilkin ◽

R.Z. Valiev ◽

...

Keyword(s):

High Pressure ◽

Phase Transitions ◽

High Pressure Torsion ◽

Co Alloys

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Formation, and mechanical and magnetic properties of bulk ferromagnetic Fe-Nb-B-Y-(Zr, Co) alloys

Journal of Materials Research ◽

10.1557/jmr.2006.0126 ◽

2006 ◽

Vol 21 (4) ◽

pp. 1019-1024 ◽

Cited By ~ 18

Author(s):

J.M. Park ◽

J.S. Park ◽

D.H. Kim ◽

J-H. Kim ◽

E. Fleury

Keyword(s):

Magnetic Properties ◽

Saturation Magnetization ◽

Amorphous Alloys ◽

Amorphous Structure ◽

Glass Forming Ability ◽

Partial Replacement ◽

Soft Magnetic ◽

Glass Forming ◽

Mold Casting ◽

Co Alloys

Fe element was partially substituted by Zr and Co in an attempt to enhance the glass-forming ability, and mechanical and soft magnetic properties of Fe74-xNb6B17Y3(Zr, Co)x (x = 3, 5, 8) amorphous alloys. Both partial replacements resulted in the enhancement of the glass-forming ability, and 3-mm diameter rods with a fully amorphous structure were prepared by a copper mold casting method. Zr and Co containing Fe-based bulk amorphous alloys exhibited high compressive fracture strength of about 4 and 3.5 GPa, respectively. However, Zr and Co induced different effects on the magnetic properties. Whereas the partial replacement of Fe by Zr was found to decrease dramatically the saturation magnetization, the partial replacement of Fe by Co provided an increase of about 25% of the saturation magnetization.

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