Fe-based Alloys Research Articles

Mechanism of stress induced irreversible magnetic anisotropy in Fe-based alloy ribbons

Fe-based amorphous and nanocrystalline soft magnetic alloys are regarded as the significant dual-green energy-saving materials because of their superior magnetic properties and straightforward fabrication procedure. As such, they have attracted much attention in the fields of the electronic information and electrical power. In this work, Fe<sub>73.5</sub>Cu<sub>1</sub>Nb<sub>3</sub>Si<sub>13.5</sub>B<sub>9</sub> (%) amorphous alloy ribbon is subjected to various physical ageing treatments in nitrogen atmosphere. These treatments include annealing at 540 ℃ for 30 min under different tensile stresses and isothermal tempering without tensile stress for several cycles. The origin of stress-induced magnetic anisotropy is investigated through using dynamic strain analysis, the longitudinally driven giant magento-impedance effect, and synchrotron radiation X-ray diffraction. In the process of tensile stress annealing, it is found that the axial strain of ribbon is elastic strain when annealing temperature is below the glass transition point, and plastic strain when annealing temperature is above the glass transition point; the precipitation of nanocrystalline phase has a pinning effect on amorphous matrix, which slows down the strain rates and makes the tend stable. Additionally, isothermal tempering studies show that the stress-induced magnetic anisotropy and lattice plane anisotropy have different relaxation patterns. It is found through numerical fitting that the stress-induced magnetic anisotropy can reach a stable value of 0.144 by infinite tempering, whereas the lattice plane anisotropy can only relax to zero by finite tempering. A model of nanocrystalline grain distribution anisotropy is developed to re-examine the origin of stress-induced magnetic anisotropy. It supports a viewpoint that the nanocrystalline grain distribution anisotropy <inline-formula><tex-math id="M4">\begin{document}$\Delta \delta $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20221509_M4.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20221509_M4.png"/></alternatives></inline-formula> is responsible for the stress-induced irreversible magnetic anisotropy <inline-formula><tex-math id="M5">\begin{document}${K_{\text{d}}}$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20221509_M5.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20221509_M5.png"/></alternatives></inline-formula>, and that their relationship can be described as a following function: <inline-formula><tex-math id="M6">\begin{document}${K_{\text{d}}} = k\Delta \delta $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20221509_M6.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20221509_M6.png"/></alternatives></inline-formula>. Therefore, it is proposed that the stress-induced anisotropy originates from a synergistic interaction between the lattice plane anisotropy and the nanocrystalline grain distribution anisotropy in Fe-based alloy ribbon. This work has important implications for understanding the mechanism of the stress-induced magnetic anisotropy.

Analysis of The Removal Mechanism of Ferroalloy by Acidithiobacillus Ferrooxidans

Bio-machining technology is widely recognized as an environmentally friendly processing method for metals removal. In order to reveal the removal mechanism of ferroalloy corroded by Acidithiobacillus Ferrooxidans, ferroalloy workpieces were prepared by mixing 50% the powder of Fe with Co, Ni and Cu, and they were sintered with vacuum hot-pressing, A set of material removal experiments were carried out by shaking the ferroalloy with the bacterial strain culture solution of Fe3+ level at 5.5 g/L, and the material removal amount, surface morphology and roughness, and electrochemical characteristics of ferroalloy workpieces were determinated. The results showed that the Fe-based alloys containing Co, Ni, Cu, and Sn can be bio-machined, and the surface roughness of the ferroalloys significantly increased after machining. The material removal amount (MRA) of 8 hours of bio-machining ranked in the order of Fe50Co (42.3) >Fe50Cu (36.4) > Fe50Ni (21.6)>Fe50Sn (14.3). The MRA of each ferroalloy increased with the processing time, and the results could be fitted in a power function with machining time. In conclusion, the activity of the metal, the passivation on the alloy surface and the accelerated corrosion of the inert metal on the active metal were the three most important factors affecting MRA of ferroalloys. The additional reaction between Fe and newly generated metal ions by Fe3+, as well as the uneven reaction layer of workpieces was involved in the process of bio-machining.

The Effect of Stress-Annealing on the Mechanical and Magnetic Properties of Fe-Based Metal-Amorphous Nano-Composite Soft Magnetic Alloys

The Effect of Stress-Annealing on the Mechanical and Magnetic Properties of Fe-Based Metal-Amorphous Nano-Composite Soft Magnetic Alloys

Calculation Assisted Composition Design of Fe-Based Amorphous Alloys

Calculation Assisted Composition Design of Fe-Based Amorphous Alloys

The effect of temperature modification on the properties of Fe-based amorphous alloys

The effect of temperature modification on the properties of Fe-based amorphous alloys

Effects of Interfacial Interaction between Metal and Process Control Agents During Ball Milling on the Microstructure of the Milled Fe-Based Nanocrystalline Alloy Powder

Effects of Interfacial Interaction between Metal and Process Control Agents During Ball Milling on the Microstructure of the Milled Fe-Based Nanocrystalline Alloy Powder

Microstructure and Tribological Behavior of Fe-Based Amorphous Alloy Fabricated by Plasma Spraying and Laser Remelting

Microstructure and Tribological Behavior of Fe-Based Amorphous Alloy Fabricated by Plasma Spraying and Laser Remelting

Magnetic Properties, Anisotropy, and Domain Structure of Fe-Based Nanocrystalline Alloy Induced by Continuous Stress-Annealing Treatment

Magnetic Properties, Anisotropy, and Domain Structure of Fe-Based Nanocrystalline Alloy Induced by Continuous Stress-Annealing Treatment

Local crystallization investigation of amorphous alloys using a two-dimensional detector by X-ray diffraction method

Amorphous alloys without a crystalline structure exhibit excellent soft magnetic properties but are difficult to machine due to their tough mechanical properties. The authors have proposed a new machining method that improves machinability by crystallizing only the local regions involved in machining, thereby reducing local strength and toughness. To realize this method, it is necessary to evaluate the crystallinity of the local area nondestructively, but it is difficult to detect a local area of crystals precipitated in amorphous materials by the conventional X-ray diffraction method (sin2ψ method). In this paper, we attempted to investigate the crystallinity of the local area using a two-dimensional X-ray diffraction method (2D method) with a two-dimensional detector. Fe-based amorphous alloys were locally crystallized using an ultrashort pulsed laser with a beam diameter of about 66 μm. Then, it was revealed that the 2D method can evaluate even a small area of crystallization within several tens of micrometers.

Mn Content Optimum on Microstructures and Mechanical Behavior of Fe-Based Medium Entropy Alloys

Mn Content Optimum on Microstructures and Mechanical Behavior of Fe-Based Medium Entropy Alloys

Effect of Hvof Spraying Process on Particle Behavior of Fe-Based Amorphous Alloy Coatings

Effect of Hvof Spraying Process on Particle Behavior of Fe-Based Amorphous Alloy Coatings

Critical Influence of Glassy State on Nanocrystallization of Amorphous Precursors in Fe-Based Nanocrystalline Soft Magnetic Alloys

Critical Influence of Glassy State on Nanocrystallization of Amorphous Precursors in Fe-Based Nanocrystalline Soft Magnetic Alloys

Friction and wear behavior under oil lubrication conditions of amorphous-nanocrystalline composite coatings deposited via HVAS

To prolong the service life of heavy-duty vehicle engine parts subject to wind and sand exposure, a FeCrMoWBRe amorphous-nanocrystalline composite coating was prepared via high-velocity arc spraying for its higher wear resistance than the traditional one. The adhesive strength of the coating is approximately 60.5 MPa, the hardness is approximately 13.3 GPa, and H 3 /E r 2 is 0.07 GPa, indicating that the coating has excellent wear resistance. Under the condition of oil lubrication, the wear rates of the coating under different loads (50–150 N) are in a range of (0.993–250) × 10 −7 mm 3 ·N −1 ·m −1 ; the coating performance is most stable under low and medium loads (50–100 N). It is proved that, abrasive and fatigue wear are the predominant wear mechanisms under low and medium loads (50–100 N), while abrasive, fatigue, and delamination friction as well as wear mechanisms are the dominant under higher loads (e.g., 125 and 150 N) for the coating. After adding abrasive particles, the wear rates of the coating under different loads are in the range of (3.6–259) × 10 −7 mm 3 ·N −1 ·m −1 ; the wear amount is not significantly increased under higher loads (125 and 150 N). The wear mechanism is almost the same under this condition. These results indicate that the coating performs stably under low and medium loads and shows resistance to abrasive particles, especially under higher loads. • A Fe-based amorphous-nanocrystalline alloy composite coating with excellent wear resistance was prepared by HVAS. • The influences of load and the third-body abrasive particles on the wear resistance were investigated. • The results have guiding significance to the wear resistance of heavy-duty vehicle engine parts in high wind-sand area.

Effects of annealing time on nanoscale structural heterogeneity and magnetic properties of Fe<sub>80</sub>Si<sub>9</sub>B<sub>10</sub>Cu<sub>1</sub> amorphous alloy

The evolution of nanoscale structural heterogeneity and its effect on magnetic properties of Fe<sub>80</sub>Si<sub>9</sub>B<sub>10</sub>Cu<sub>1</sub> amorphous alloy during structural relaxation after being annealed for different times are investigated in this work. The nanoscale structural heterogeneity is found to degenerate gradually with relaxation by using the small-angle X-ray scattering and atomic force microscope. Combined with Mössbauer spectroscopy analysis results, the enhanced comprehensive soft magnetic properties of the relaxed alloys can be attributed to the degeneration of nanoscale structural heterogeneity. From the flow unit model, the volume fraction of flow units decreases with relaxation proceeding, and some of the flow units annihilate and transform into the ideal elastic matrix. On the one hand, the relaxed sample with greater packing density has stronger magnetic exchange interaction and higher saturation magnetic flux intensity. On the other hand, the number density of quasi-dislocation dipoles decreases with the annihilation of flow units in the relaxation process, leading the pinning effect of the domain wall to be weakened. Consequently, the magnetic anisotropy decreases after relaxation, which results in the reduction of coercivity. In this work, the structural mechanism of the evolution of magnetic properties in the relaxation process of Fe<sub>80</sub>Si<sub>9</sub>B<sub>10</sub>Cu<sub>1</sub> amorphous alloy is investigated from the perspective of structural heterogeneity, which is helpful in establishing the correlation between the structure and magnetic properties of Fe-based amorphous alloys.

Influence of Stress-Induced Anisotropy on Domain Structure and Magnetic Properties of Fe-Based Nanocrystalline Alloy Under Continuous Tension Annealing

Influence of Stress-Induced Anisotropy on Domain Structure and Magnetic Properties of Fe-Based Nanocrystalline Alloy Under Continuous Tension Annealing

Evaluation of Hall-Petch Coefficient at Grain Boundaries of Fe-based Alloys by Nanoindentation Method

Evaluation of Hall-Petch Coefficient at Grain Boundaries of Fe-based Alloys by Nanoindentation Method

Microstructure and Corrosion Behavior of Fe-Base Alloy Composite Coatings by Supersonic Plasma Spraying

Microstructure and Corrosion Behavior of Fe-Base Alloy Composite Coatings by Supersonic Plasma Spraying

Development of an Fe-Based Alloy with Reinforced Austenite and Packet Lath Martensite as Filler Metals for 9% Ni Steel

Development of an Fe-Based Alloy with Reinforced Austenite and Packet Lath Martensite as Filler Metals for 9% Ni Steel

Atomic insight into iron corrosion exposed to supercritical water environment with an improved Fe-H2O reactive force field

Waterside anti-corrosion of Fe-based alloys is one of the great challenges for supercritical water reactors. Herein, an improved Fe-H2O reactive force field (ReaxFF) is constructed to understanding the Fe corrosion mechanism at the atomic scale. Using molecular dynamics simulations, the corrosion of Fe (100) and Fe (110) in supercritical water was investigated. It was found that oxidation and hydrogen evolution reactions occurred along with Fe dissolution; the corrosion rate on Fe (100) was faster than that on Fe (110) in the early stage, but the reverse occurred on a longer time scale; and the precipitation of ferrous hydroxide at the initial stage led to the formation of an oxidation layer, where FeO and Fe3O4 were the dominant products. The present ReaxFF can become a crucial tool for corrosion research on Fe-based alloys.

Comparative study of the electronic structure and optical properties of the Heusler alloys Co2MGa and Co2MAl (M = Fe and Ni)

The electronic structure and optical properties of the Heusler alloys Co2NiGa, Co2NiAl, Co2FeGa, and Co2FeAl are reported and compared in this work. In the Fe-based alloys, Co2FeGa and Co2FeAl, the electronic structure is found to have 100% spin polarization with the indirect energy gap in the [Formula: see text]-[Formula: see text] direction, whereas in Co2NiGa and Co2NiAl, the density of states is metallic in both spin projections with spin polarization of 55% (Co2NiGa) and 37% (Co2NiAl). Total and Co partial magnetic moments of all Heusler alloys for the optimized lattice parameters were found in a good agreement with previous calculations and experimental data. The frequency dependence of the real and imaginary parts of the complex dielectric constant for the Heusler alloys is studied in the spectrum region of 0.08–5 eV. The research results are discussed based on the performed calculations of the electronic structure. It was found that the character of variations of the spectral parameters of the alloys is typical for media with the metallic conductivity. In the IR region, the mechanism of the intraband acceleration of electrons by the light wave field dominates. The significant changes in the optical spectrum, magnetic moment, spin polarization and electronic structure were revealed in Co2MGa and Co2MAl for different M atoms which motivate further investigations of the Co-based Heusler alloys as promising materials for spintronics.