Properties Of Fe-based Amorphous Alloys Research Articles

Catalytic properties of Fe-based amorphous alloys based on LPBF

Laser Powder Bed Fusion (LPBF) additive manufacturing technology has the advantages of high forming accuracy and rapid cooling. It is expected to overcome the limitations of forming difficulties in amorphous alloys and provide a new opportunity for the production of amorphous alloy structural parts. In this paper, FeSiBCrC amorphous alloy powder was used to prepare Fe-based amorphous alloy samples by LPBF technology. In view of the excellent properties of Fe-based amorphous alloy, the catalytic degradation performance of Fe-based amorphous alloy samples prepared by LPBF was systematically investigated. The catalytic degradation performance of the Fe-based amorphous alloy was optimised by changing the reaction conditions. In the methyl orange (MO) dye degradation experiment, the degradation rate reached 90.99% within 10 min. Increasing the sample dosage and reaction temperature can improve the degradation efficiency, but excessive addition of H2O2, raising the pH and the initial dye concentration will reduce the degradation efficiency. In addition, in the cyclic catalytic experiment, it was found that it has self-renewing performance, and the degradation efficiency was still higher than 95% within 35 minutes after repeated degradation 12 times. Fe-based amorphous alloy catalysts prepared on the basis of LPBF have good catalytic activity and will provide economical and effective technical support for wastewater treatment.

Effect of Laser Irradiation and Tensile Stress on Microstructure and Magnetic Properties of Fe-Based Amorphous Alloys.

The effect of laser irradiation and tensile stress on the microstructure and soft magnetic properties of the FeSiBNbCu nanocrystalline alloy prepared using a continuous laser has been investigated. The experimental results indicate that a decreased laser scanning speed provides more thermal energy to induce nanocrystals and encourage grain growth. When the scanning speed is excessively high, the crystallization process will cease due to a lack of energy to drive diffusion phase transitions. Nevertheless, the introduction of tensile stress could significantly promote crystallization in FeSiBNbCu alloy samples irradiated at these high laser scanning speeds. This phenomenon can be attributed to the augmentation of compressive thermal stress at the interface between the laser-treated track and the untreated region. This heightened compressive stress promotes the diffusivity of atoms, and, as a result, the transformation from amorphous to crystalline states can be enhanced. As the applied tensile stress increases, both grain size and crystalline volume fraction exhibit a proportional augmentation. Consequently, these changes manifest in the soft magnetic properties. The crystalline volume fraction can reach 62%, and the coercivity is 2.9 A/m at the optimized scanning speed; these values correspond to 54% and 3.3 A/m under specific tensile stress loading.

Prediction of magnetocaloric properties of Fe-based amorphous alloys based on interpretable machine learning

This study developed a machine learning model to accurately predict the isothermal magnetic entropy change (-SM) in amorphous alloys, a key parameter for evaluating magnetocaloric performance. Four machine learning algorithms were compared, and the (Extremely Randomized Trees) ETR algorithm demonstrated exceptional performance with an (R-squared) R2 value of 0.90 and a (Mean Absolute Percentage Error) MAPE of 13.31 % on the test set. Feature selection techniques, including Pearson correlation coefficient (PCC) and Recursive feature elimination (RFE), identified a subset of 7 important features: (Applied Field) Mf, δr, ΔH, ΔTm, ΔS, Tm‾, and Ec‾. The Shapley Additive Explanations (SHAP) method provided insights into feature importance and critical values. Design strategies for new alloys, using the FeZrB system as an example, were proposed based on the predictive model. The model's generalization ability was validated on other amorphous alloy systems, showcasing its wide applicability. This research contributes to the field of amorphous alloys and suggests future directions for machine learning applications.

Structural responses of heterogeneous FeB(P)CCu amorphous alloys under nanoindentation

The nano-scaled structural heterogeneity is closely associated with the magnetic softness and mechanical properties of Fe-based amorphous alloys. However, limited by the shape and size of ribbons, the details of the atomic-scale structural evolution in ribbons under external stimulation are still missing. In this work, Maxwell-Voigt model with 2 K units and 1 Mx unit was employed to investigate the structural response of FeBCCu amorphous ribbons by substitution of P for B during creeping process under nanoindentation. The P-added alloy exhibited a more sensitive mechanical response at various loading rates, especially for the reduction of hardness and the increase of maximum indentation depth and creep displacement. With the help of creep analysis using above Maxwell-Voigt model, both types of defects were inclined to be activated at a quasi-static loading mode in P-added alloy, and the small size defects seemed to be easily activated and finally coupled into large defects in the fast loading mode, revealing the atomic diffusion and reconstruction process of activated defects. These types of defects evolved into the response of structural heterogeneity to external stimulation, manifesting a large deformation behavior during creeping. This work enlightens the comprehensive insights into the evolution of structural defects in Fe-based amorphous ribbons and has certain guiding significance for the structural design of high-performance alloys.

Structural heterogeneity, β relaxation and magnetic properties of Fe-Zr-B amorphous alloys with Si and Cu additions

Despite numerous studies on β relaxation of amorphous alloys, the relationship between structural heterogeneity and β relaxation and the effect on magnetic properties of Fe-based amorphous alloys is still unknow. In this work, the structure and magnetic properties of Fe84-xZr6B10Mx (M = Si, Cu; x = 0, 0.6, 1 at%) amorphous alloys were investigated. With the increase of Si content, the negative value of average chemical affinity (∆Hchem) of the alloys is increased, leading to the synergetic enhancement in structural heterogeneity and β relaxation. In addition to this, the increase of liquid-like regions (LLRs) reduces saturation magnetic flux density (Bs) and increases coercivity (Hc). However, the addition of Cu element decreases the negative value of ∆Hchem of the alloys, resulting in weakening of structural heterogeneity and β relaxation synergetically. The reduction of LLRs has resulted in increase in Bs. Moreover, Fe-Cu atom pairs with positive enthalpy of mixing increases the local density of quasi dislocation dipoles (QDDs), resulting in the increase of Hc.

Effect of miscible and immiscible element microalloying on crystallization behavior and soft magnetic properties of Fe-P-C-B amorphous alloy

Microalloying is an efficient strategy to promote nano-crystallization of Fe-based amorphous alloys to improve soft magnetic properties. Here, the Fe-P-C-B amorphous alloy is selected as a typical system to investigate the effect of microalloying of immiscible elements (In and Sn) and miscible elements (Al, Ga and Ge) in Fe on crystallization behavior and soft magnetic properties of Fe-based amorphous alloys. Microalloying of immiscible elements leads to slightly increased energy barrier for α-Fe nuclei growth as evaluated by Kissinger equation, yielding fine and uniform α-Fe nanograins and low coercivity after annealing. In contrast, miscible elements cause high growth energy barrier, resulting in few huge α-Fe grains and large coercivity. This work suggests a strategy of obtaining amorphous-nanocrystalline alloys with good magnetic properties by microalloying of immiscible elements.

A Review of the Preparation, Machining Performance, and Application of Fe-Based Amorphous Alloys

Amorphous alloy is an emerging metal material, and its unique atomic arrangement brings it the excellent properties of high strength and high hardness, and, therefore, have attracted extensive attention in the fields of electronic information and cutting-edge products. Their applications involve machining and forming, make the machining performance of amorphous alloys being a research hotspot. However, the present research on amorphous alloys and their machining performance is widely focused, especially for Fe-based amorphous alloys, and there lacks a systematic review. Therefore, in the present research, based on the properties of amorphous alloys and Fe-based amorphous alloys, the fundamental reason and improvement method of the difficult-to-machine properties of Fe-based amorphous alloys are reviewed and analyzed. Firstly, the properties of amorphous alloys are summarized, and it is found that crystallization and high temperature in machining are the main reasons for difficult-to-machine properties. Then, the unique properties, preparation and application of Fe-based amorphous alloys are reviewed. The review found that the machining of Fe-based amorphous alloys is also deteriorated by extremely high hardness and chemical tool wear. Tool-assisted machining, low-temperature lubrication assisted machining, and magnetic field-assisted machining can effectively improve the machining performance of Fe-based amorphous alloys. The combination of assisted machining methods is the development trend in machining Fe-based amorphous alloys, and even amorphous alloys in the future. The present research provides a systematic summary for the machining of Fe-based amorphous alloys, which would serve as a reference for relevant research.

Nanoscale structural heterogeneity and magnetic properties of Fe-based amorphous alloys via Co and Ni additions

Nanoscale structural heterogeneity is a critical parameter for understanding the structure-property relationships in amorphous alloys. Herein, the small-angle X-ray scattering and atomic force microscopy were utilized to quantitatively investigate the nanoscale structural heterogeneity of the Fe80-xMxSi9B11 (M = Co and Ni; x = 0, 2, 4) amorphous alloys. The results show that the nanoscale structural heterogeneity of the amorphous alloys increases prominently with Ni substitution, but gradually decreases with the increase of Co content. Such evolution of structural heterogeneity was further verified by the changes in mechanical behavior. The microalloying of Ni can increase the plastic deformation ability and reduce the microhardness, whereas an opposite effect is found in the Co-doped alloys. Finally, Mössbauer spectroscopy reveals an enhancement in ferromagnetic exchange interaction and magnetic anisotropy with Co substitution, while the microalloying of Ni leads to a deteriorative result. Such variations in magnetic properties can be attributed to the evolution of nanoscale structural heterogeneity with Co and Ni additions. Our observation serves as a link between the nanoscale structural heterogeneity and magnetic properties, providing a new sight into understanding the structural origin of the changes in magnetic properties of Fe-based amorphous alloys.

Nanoscale structural heterogeneity perspective on the ameliorated magnetic properties of a Fe-based amorphous alloy with decreasing cooling rate

Despite that the nanoscale structural heterogeneity of amorphous alloys has been confirmed by advanced experimental observations and theoretical simulations, the underlying link between the structural heterogeneity and magnetic properties remains poorly known. In this work, the effect of cooling rate on the nanoscale structural heterogeneity and magnetic properties of Fe80Si9B11 amorphous ribbons (Fe-Si-BAR) was studied by atomic force microscopy and Mössbauer spectroscopy. The results show that the degeneration of nanoscale structural heterogeneity substantially induces an improvement in soft magnetic properties with decreasing cooling rate. Specifically, the volume fraction of flow units reduces significantly with the decrease of cooling rate, and some of the flow units annihilate and transform to the ideal elastic matrix. The structural densification and reduction of the number density of quasidislocation dipole result in an enhancement in ferromagnetic exchange interaction and weakening of magnetic anisotropy. Therefore, the saturation magnetic flux density increases and coercivity decreases with reducing cooling rate. Our results provide new insight into understanding the structural mechanism in the ameliorated magnetic properties of Fe-based amorphous alloys with decreasing cooling rate.

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 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.

Structural and Phase Evolution upon Annealing of Fe76Si9−xB10P5Mox (x = 0, 1, 2 and 3) Alloys

Alloying elements play an important role in adjusting the magnetic and thermal properties of Fe-based amorphous alloys. In this work, the effect of Mo addition on the thermal stability, structural evolution, and magnetic properties of Fe76Si9B10P5 metallic glass was studied. The study revealed that the substitution of a small amount of Mo (1 at.%) for Si enhances the glass-forming ability (GFA) but reduces the thermal stability of the alloy, causing a reduction of the supercooled liquid region. Substitution of up to 3 at.% Mo for Si lowers the Curie temperature from 677 to 550 K and the saturation magnetization drops from 160 to 138 Am2/kg. The structural evolution was evaluated by annealing the glassy samples at different temperatures, revealing that the crystallization proceeds in multiple steps, beginning with the formation of different iron borides (FeB, Fe2B, FeB2 and Fe23B6) followed by transformation to a mixture of more stable phases.

Anisotropic crystallization and magnetic properties of Fe-based amorphous alloys induced by ion inclined bombardment

The structures and magnetic properties of Fe73.5Si13.5B9Nb3Cu1 amorphous alloys after ion bombardment were investigated. The needle-like structure and granular structure nanocrystalline was respectively formed for the samples bombarded by ion beam at the incident angle of 75° and 90°, which was explained according to the crystallization and crystal growth under anisotropic stress produced by ion beam inclined bombardment. The ion beam inclined bombardment produced a compressive and parallel stress on the sample, the compressive stress promoted the nucleation by decreasing the critical nucleation free energy and the parallel stress caused the directional migration of atoms. Low incident angle ion bombardment only led to the structure relaxation, and high incident angle ion bombardment produced a large compressive stress on the sample, which then induced the crystallization of amorphous alloys. The anisotropic crystallization caused by ion beam inclined bombardment resulted in the increase of magnetic anisotropy and then improved the high-frequency properties.

Tailoring soft magnetic properties of Fe-based amorphous alloys through C addition

It is known that developing Fe-based amorphous alloys with the saturation flux density (Bs) higher than 1.65 T is a major challenge. In present work, effects of C addition on magnetic properties of Fe-based amorphous alloys were systematically studied. It has been found that the addition of C can significantly increase the saturation flux density (Bs) and the magnetic flux density at 800 A/m (B800) of the Fe–B–C–Si–P amorphous alloys. After the addition of C, the Bs of the amorphous alloys increase from 1.61 T (Fe83B13Si3P1) to 1.65–1.71 T (Fe83B13-xCxSi3P1, x = 1.5, 2, 3 and 4). The Fe83B10C3Si3P1 amorphous alloy possesses excellent soft magnetic properties with high Bs of 1.71 T and low Hc of 1.5 A/m. It shows that density increase of the alloys and weakened metalloid-sp/metal-d bonding caused by C addition contribute to the increment of Bs. It suggests that the newly developed high-performance amorphous alloys possess great potential in application.

Structural and Magnetic Characterization of Fe-Based Amorphous Alloy Prepared by Microwave Annealing Treatment

Fe-based nanocrystalline soft-magnetic alloy presents the advantages of high permeability and low hysteresis loss and is widely used in the power electronics industry due to its excellent soft-magnetic properties. The effects of microwave annealing on the crystallization process and properties of Fe80.5Si10B8Cu1Nb0.5 amorphous alloy have been studied by differential scanning calorimetry, x-ray diffraction analysis, and vibrating-sample magnetometry. The crystallization process of Fe80.5Si10B8Cu1Nb0.5 amorphous alloy consists of two stages: α-Fe(Si) phase and Fe2B phase. The microwave annealing process enables a significant improvement in the soft-magnetic properties of Fe-based amorphous alloy, with the optimum magnetic properties being obtained for the alloys annealed at 1000 W for 10 min.

Effect of cobalt addition on the microstructural evolution, thermal stability and magnetic properties of Fe-based amorphous alloys

The role of cobalt and its influence on the structure, and thermal and magnetic performance of a (Fe1-xCox)77Si8B10P5 system with x = 0, 0.2 and 0.4 was investigated. It was possible to obtain amorphous alloys throughout the system by the melt spinning technique. Therefore, it can be stated that certain amounts of Co do not affect glass forming ability, allowing Fe-based alloys to be obtained with amorphous structure. 19% enhancement of the Curie temperature was observed with Co addition, indicating an increase in magnetic stability at high temperatures; while saturation magnetization presented a slight reduction. Crystallization mode changed from one to two exothermic peaks, and the phases found in the system corresponded to α-Fe(Si), Fe2B and Fe3(B, P) for the Co-free alloy, and α-Fe(Co)Si, Fe3(B, P), Co2Si, Co2B, Fe3P, and FeB for the Co-containing alloys.

Effects of W Addition on the Electrochemical Behaviour and Passive Film Properties of Fe-Based Amorphous Alloys in Acetic Acid Solution

The electrochemical behaviour and passive film properties of Fe–Cr–Mo–W–C–B–Y amorphous alloys in acetic acid solution were investigated. The potentiodynamic polarisation and Nyquist curves demonstrated that W addition significantly enhanced the corrosion resistance. Mott–Schottky plots and angle-resolved X-ray photoelectron spectra indicated that passive films with different W contents exhibited dipolar (p–n) semiconducting characteristics separated by flat-band potentials. The outer and inner oxide layers of the passive films were modified by reducing the acceptor and donor densities. Moreover, W addition favoured the formation of a thicker and more stable passive film to inhibit the dissolution of alloy elements.

Effect of boron on the magneto-caloric effect in Fe91−x Zr9B x (x = 3, 4, 5) amorphous alloys

In the present work, Fe91−x Zr9B x (x = 3, 4, 5) amorphous alloys were employed to study the effect of boron on the magnetic properties of Fe-based amorphous alloys. Thermal and magnetic properties of Fe91−x Zr9B x (x = 3, 4, 5) amorphous alloys were measured. Although the amorphous alloys show similar glass forming ability, peak values of magnetic entropy change (−ΔS m peak ) and Curie temperature (T c) near room temperature improve significantly with increasing boron content. The improved T c, as well as −ΔS m peak , is due to the enhanced direct interaction between Fe atoms, which is ascertained by the increasing µ eff with boron addition in the Fe91−x Zr9B x (x = 3, 4, 5) amorphous alloys.

Study of the effects of metalloid elements (P, C, B) on Fe-based amorphous alloys by ab initio molecular dynamics simulations

In order to understand the effects of the metalloid elements M (M: P, C, B) on the atomic structure, glass formation ability (GFA) and magnetic properties of Fe-based amorphous alloys, Fe80P13C7, Fe80P14B6 and Fe80B14C6 amorphous alloys are chosen to study through first-principle simulations in the present work. The atomic structure characteristic of the three amorphous alloys is investigated through the pair distribution functions (PDFs) and Voronoi Polyhedra (VPs) analyses. The PDFs and VPs analyses suggest that the GFA of the three alloys dropped in the order of Fe80P13C7, Fe80P14B6, and Fe80B14C6, which is well consistent with the experimental results. The density of state (DOS) of the three amorphous alloys is calculated to investigate their magnetic properties. Based on the DOS analysis, the average magnetic moment of Fe atom in Fe80P13C7 and Fe80P14B6 amorphous alloys can be estimated to be 1.71 μB and 1.70 μB, respectively, which are in acceptable agreement with the experimental results. However, the calculated average magnetic moment of Fe atom in Fe80B14C6 amorphous alloy is about 1.62 μB, which is far less than the experimental result.

Improvement of glass forming ability and soft magnetic properties of Fe-C-Si-P amorphous alloys through a flux treatment technique

Effects of fluxing treatment on the glass forming ability and magnetic properties of Fe-based amorphous alloys prepared using industrial raw materials have been studied. The partially amorphous Fe76Si8P9C7 rod with the diameter of 1 mm was prepared by suction casting technique from the fluxed master alloy based on the industrial raw materials, while the alloy rod with the diameter of 1 mm obtained from the un-fluxed master alloy does not involve any amorphous phase. Melt spun ribbons prepared using the fluxed master exhibited lower the coercivity H c and power loss than those for ribbons prepared using the un-fluxed master alloy. These beneficial effects should be attributed to the purification of the master alloy through flux treatments. The results reveal that fluxing technique can play an important role in the development of Fe-based bulk metallic glasses using industrial raw materials with relatively low purities.