Fe-based Metallic Glass Research Articles

Study on the irradiation damage in Fe-based metallic glasses induced by Ne10+ ions

• High enery and high charged Ne 10+ ions made the atoms of Fe 80 Si 7 B 13 aggregation. • The uneven range of atoms in Fe 80 Si 7 B 13 is larger than that by SRIM. • Potential energy of Ne 10+ ions caused sputtering and then produced nano-defects. • Free volume is the essential reseaon for materials have good irradiation resistance. Due to the long-range disordered structure, metallic glass could be used as a candidate for radiation-resistant materials. The article showed the influence of Ne 10+ ions irradiation on the microstructure, atomic arrangement and defects of Fe-based metallic glasses. Metallic glasses Fe 80 Si 7 B 13 and Fe 68 Zr 7 B 25 remained amorphous after irradiation at different fluence. However, the atomic arrangement of Fe 80 Si 7 B 13 became uneven after irradiation, and a trend toward ordering appeared. The thickness of the uneven layer of atoms was greater than the calculated concentration distribution range of Ne 10+ ions by SRIM. After irradiation, raised and pitted nano-structure defects appeared on the surface of Fe-based metallic glasses. The surface roughness of Fe 80 Si 7 B 13 increased slightly, while the surface reflectivity decreased, and the number of vacancy-type defects in Fe 80 Si 7 B 13 was slightly increased. These results provide a basic description for the irradiation damage of Fe-based metallic glass and give a evaluation of potential applications of the metallic glass.

Microstructure and mechanical properties of Fe-based bulk metallic glass composites fabricated by selective laser melting

Selective laser melting of ductile Cu particles reinforced Fe-based bulk metallic glass composites (Fe-based BMGCs) were used to break geometric complexity limitations and improve the mechanical properties. In this work, the effects of Cu content on microstructure, mechanical properties and fracture deformation behavior of Fe-based BMCGs were systematically investigated. The appropriate Cu addition can decrease stress concentration by altering elements distribution, especially C element which will increase the brittleness of BMGs and lead to crack formation. The crack-free Fe-based BMGCs with a well bonding interface between the secondary phase and matrix is presented with 40 vol.% Cu addition. The improved plasticity of BMGCs with Cu addition originates from the inhibition of shear bands via formation of multiple shear bands. This work demonstrates that introducing tough secondary phase into BMGs is an effective method to improve their formability and performance.

The influence of successive irradiation of He and H ions on the structure, morphology and property of metallic glass Fe80B13Si7

500 keV He ions and 250 keV H ions was used to irradiate the metallic glass Fe80B13Si7. When the fluence increased to 2 × 1017 He ions/cm2 + 1 × 1018H ions/cm2 or 1 × 1018 He ions/cm2 + 5 × 1017H ions/cm2, no crystallization or obvious surface damage appeared in the metallic glass. Compared with the case of He ions or H ions irradiation, the successive irradiation of both ions roughened the surface of the Fe-based metallic glass. Under the successive irradiation, the He bubble layer thickened due to the diffusion of bubbles, and the size of bubbles decreased while the number density increased. The metallic glass Fe80B13Si7 still maintained good soft magnetic property under the successive irradiation, while its saturation magnetic induction intensity and coercive force changed slightly.

Effect of Ni substitution on the formability and magnetic properties of Gd50Co50 amorphous alloy**Project supported by the National Natural Science Foundation of China (Grant Nos. 51671119 and 51871139), the Chongqing Research Program of Basic Research and Frontier Technology, China (Grant No. cstc2018jcyjAX0329 and cstc2018jcyjAX0444), and the Key Project of Science and Technology Research Program of Chongqing Education Commission of China

A small amount of Ni was added into the binary Gd50Co50 amorphous alloy to replace Gd in order to obtain ternary Co50Gd50 − xNix (x = 1, 2, and 3) amorphous alloys. Compared to the binary Gd50Co50 amorphous alloy, the Co50Gd50 − xNix amorphous alloys show an enhanced Curie temperature (TC) with a weakened formability. The maximum magnetic entropy change () of the Co50Gd50−xNix amorphous alloys is found to decrease with the increasing TC. The adiabatic temperature rise (ΔTad) of the Co50Gd47Ni3 amorphous alloy is superior to that of the Fe-based metallic glasses at room temperature. The variation of the TC and of the Gd50Co50 amorphous alloy with Ni addition, and the mechanism involved, were discussed.

Fabrication of Fe-based metal glass microelectrodes by a vertical liquid membrane electrochemical etching method.

The excellent physical and chemical properties of metallic glasses and the absence of crystal defects make them ideal materials for the preparation of microelectrodes. A vertical liquid membrane electrochemical etching method is proposed here for the fabrication of microelectrodes from the Fe-based metallic glass Fe77.5B15Si7.5. With this method, insoluble electrolysis products are kept away from the processing area, and the nonuniformity of the diffusion layer that occurs in traditional transverse liquid membrane electrochemical etching is reduced. Simulations of the potential distribution and the current density distribution are carried out in COMSOL software, and the simulation results are verified by experiments. The passivation characteristics of the Fe77.5B15Si7.5 metallic glass in H2SO4 and H3PO4 electrolytes are studied. The effects of processing voltage on electrode morphology and surface quality are studied experimentally. Micropins with good tip size can be prepared in the active dissolution stage in 0.1M H2SO4 solution, and high-aspect-ratio cylindrical microtool electrodes with high surface quality can be fabricated in the transpassivation stage in 80% H3PO4 electrolyte with high machining stability.

On the correlation between glass forming ability (GFA) and soft magnetism of Ni-substituted Fe-based metallic glassy alloys

The present work aims to investigate the mechanism of glass formation and correlates it to the soft magnetism of Ni-substituted Fe-B-Nb alloys. The impact of ferrous Ni on the mechanism of glass formation and soft magnetism of Fe-based bulk metallic glasses was critically analyzed. By quantifying glass forming ability and soft magnetic characteristic for varying degrees of substitution, we observe a maximum in glass forming ability together with a minimum coercivity, which we suggest is due to an increased atomic packing density of the glassy phase. Interestingly, a monotonic increase of Curie temperature with increasing substitution of Ni was observed, which could be attributed to a reduction of an antiferromagnetic Fe-Fe interaction in the glassy iron-rich matrix. The overarching goal of this study is to explore the underlying mechanisms of enhanced glass forming ability, improved soft magnetic properties, and increased Tc of Ni-substituted Fe-based glassy alloys.

Influence of gadolinium and dysprosium substitution on magnetic properties and magnetocaloric effect of Fe78−xRExSi4Nb5B12Cu1 amorphous alloys

Amorphous Fe78−xRExSi4Nb5B12Cu1 (RE = Gd, Dy) ribbons with different RE contents were prepared by melt spinning to investigate the effect of heavy rare earth (Gd, Dy) substitution on the hyperfine structure, magnetic properties and magnetocaloric effect. The Curie temperature of RE substituted alloys, hyperfine field and magnetic moments of Fe atoms initially increase up to 1 at% RE content and then decrease monotonously for increasing RE content up to 10 at%. The dependence of magnetic entropy change (–ΔSM) and refrigeration capacity (RC) of the alloys on RE contents displays the same tendency. The RCAREA values of the alloys substituted with 1 at% Gd and Dy are similar to those of recently reported Fe-based metallic glasses with enhanced RC values compared with those of Gd5Ge1.9Si2Fe0.1. Enhanced –ΔSM and RC values, negligible coercive force and hysteresis commonly make these Fe78−xRExSi4Nb5B12Cu1 amorphous alloys as low-cost candidates for high-temperature magnetic refrigeration.

In-situ investigation of crystallization and structural evolution of a metallic glass in three dimensions at nano-scale

The crystallization behaviour of metallic glasses (MGs) has been investigated since the discovery of these important functional materials in order to optimize their synthesis procedures and improve their performances. Methods including powder X-ray diffraction and transmission electron microscopy are usually combined to characterize the crystalline structure in these “amorphous” materials. Until now, these methods, however, have failed to show the crystallization of individual crystals in three dimensions. In this work, in-situ Bragg coherent X-ray diffraction imaging (BCDI) reveals the growth and the strain variation of individual crystals in the Fe-based MGs during annealing. There is preferential growth along the surface of the MG sample particles during the crystal formation and fractal structure formation around the developing crystal surfaces; there is also strain relaxation happening from the inner parts to the surfaces of the developing crystals while cooling. The work leads to propose that during the crystallization of Fe-based MGs, the growth of the individual crystals follows a two-step procedure; and at higher temperature after the first crystallization period of the Fe-based MGs, the crystallization of α-Fe could be a competitive process between the growth of α-Fe crystals and the erosion from other elements.

Large magnetic entropy change and adiabatic temperature rise of Fe85B12La3 amorphous alloy

A newly developed Fe85B12La3 amorphous alloy with outstanding magneto-caloric effect (MCE) is reported. The glass forming ability of the Fe85B12La3 ternary alloy is good enough for it to be fabricated into amorphous ribbons. Magnetic and magnetocaloric properties of the amorphous alloy were examined. The Fe85B12La3 amorphous ribbon exhibit outstading MCE of a soft magnetic amorphous alloy with the −ΔSmpeak value is about 1.08 Jkg−1K−1 under 1 T, 1.82 Jkg−1K−1 under 2 T, 2.46 Jkg−1K−1 under 3 T, 3.04 Jkg−1K−1 under 4 T and 3.59 Jkg−1K−1 under 5 T at the Curie temperature (Tc) of 477.5 K, and the maximum adiabatic temperature rise (ΔTad) and the refrigeration cooling power is comparable to or even larger than those of other Fe-based metallic glass. The Fe85B12La3 amorphous alloy among the reported Fe-based amorphous alloys, indicating that the amorphous alloy is a good candidate for magnetic refrigerants near its Curie temperature.

Porous composite architecture bestows Fe-based glassy alloy with high and ultra-durable degradation activity in decomposing azo dye

Since the treatment of wastewater containing azo dye presents problems worldwide, it is important to seek effective materials and technology for the purification of wastewater containing azo dye. Fe-based metallic glasses have been identified as promising materials for the decomposition of dyeing wastewater due to their high chemical activity resulting from their amorphous structure. It is imperative to further improve their degradation performance, and especially their durability, for potential application in wastewater purification. Here, composite structures constructed of porous Ni and amorphous Fe78Si9B13 powder with markedly enhanced degradation performance in Orange II solution were obtained by utilizing a magnet. Due to the favorable effects of structural electrocatalysis and high dispersity of the distinctive porous architecture in addition to its self-cleaning properties, the solid-liquid interface exhibited strong, continuous electrical and mass transport, and a compelling improvement in degradation performance was achieved. Based on degradation tests and spectrum analysis, the kinetic rate was improved over 11-fold. Moreover, ultra-high durability over 100 cycles was revealed in cycling tests. The results indicate that wastewater degradation performance can be greatly enhanced by properly combining Fe-based metallic glasses with porous material.

Fe-based metallic glass reinforced FeCoCrNiMn high entropy alloy through selective laser melting

Improving the comprehensive mechanical properties of metallic materials has attracted great attentions. Here, FeCoCrNiMn high entropy alloy composite with combined high strength and toughness was fabricated by selective laser melting. The intriguing finding is that two different high entropy phases in addition to amorphous phase were detected at the high-entropy alloy and metallic glass interfacial region. With increasing the fraction of Fe-based metallic glass, the composite exhibited enhanced strength above 1000 MPa and excellent fracture toughness over 100 MPa m1/2, demonstrating potential engineering applications. The above scenario is fundamentally understood according to the high mixing entropy and sluggish effects, as well as the little atomic size difference that facilitates the generation of new high entropy phase. The combined high strength and toughness of the composite is well understood in terms of the dispersion strengthening.

Fe-Based Metallic Glasses and Dyes in Fenton-Like Processes: Understanding Their Intrinsic Correlation

Fe-based metallic glasses have been demonstrated as effective heterogeneous catalysts in Fenton-like processes for dye degradation. Yet, currently corresponding studies have limitations due to the limited study object (dyes) and the correlation between metallic glasses and dye pollutants in Fenton-like processes is still not comprehensively studied. Accordingly, this work intensively investigated the thermal catalytic behavior correlations between two Fe-based metallic glasses (Fe78Si9B13 and Fe73.5Si13.5B9Cu1Nb3) and eight different dyes. Results indicated a lower activation energy in the more active metallic glass and a dependence of the activation energy of Fe-based metallic glasses in dye solutions. In addition, a high H2O2 concentration led to a declined catalytic efficiency but a photo-enhanced Fenton-like process overcame this limitation at high concentration of H2O2 due to the decrease of pH and enhancement of irradiation. Furthermore, the average mineralization rates of Fe78Si9B13 and Fe73.5Si13.5B9Cu1Nb3 have been measured to be 42.7% and 12.6%, respectively, and the correlation between decolorization and mineralization revealed that a faster decolorization in a Fenton-like process contributed to a higher mineralization rate. This work provides an intrinsic viewpoint of the correlation between Fe-based metallic glasses and dyes in Fenton-like processes and holds the promise to further promote the industrial value of metallic glasses.

Ultrasonic vibration-assisted electrical discharge machining on Fe-based metallic glass by adding conductive powder

In this study, Fe-based metallic glass was machined by the Electrical discharge machining process with the ultrasonic vibration assisting and conductive aluminum powder adding. Fe-based metallic glass possess high strength, high hardness, and very brittle characteristics. The processing parameters include peak current, duration time, ultrasonic power, and aluminum powder concentration. After completing the experiments, the quality characteristics such as surface roughness, processing time and electrode wear quantity were also analyzed. Compared with experimental results without the ultrasonic vibration-assisting and conductive aluminum powder adding, the surface roughness and processing time is reduced by 48.8% and 40.3% after UV-assisted EDM at the aluminum powder concentration of 1.0 × 10 -2 wt% respectively. The machined Fe-based metallic glass is still an amorphous material without the crystal structures generation under XRD identification.

Water dissociation and hydrogen evolution on the surface of Fe-based bulk metallic glasses.

Fe-Based bulk metallic glasses (BMGs) with a composition of Fe48Cr15Mo14C15B6Y2 have recently been reported with good application performance due to their excellent mechanical and chemical properties, showing excellent corrosion resistance, remarkable forming and processing ability, ultrahigh yield strength and large elasticity. Here, we report on a new functional application for such Fe-based BMGs, which can exhibit better catalytic performance than the pristine Fe surface. The hydrogen evolution and dissociation processes of one and two H2O molecules on both BMG and pristine Fe surfaces are investigated using first-principles calculations. The energy barriers of the dissociation processes on the BMG surface are lower than those on the pristine Fe surface. Moreover, the structural configurations along the dissociation path during hydrogen evolution show that it is easier for H2O molecules to dissociate into H2 on the surface of the BMG, rendering it a more active catalyst than the pristine Fe surface. Analyses on the electronic structures show further evidence that the BMG surface has a stronger ability to facilitate charge transfer at the interface and is more inclined to accept transferred charges, thereby promoting its catalytic activity. These findings shed light on understanding the functional applications of BMGs and are anticipated to be highly meaningful for further experimental investigations.

Newly Developed Quaternary Ti- and Fe-Based Thin Film Metallic Glasses for Potential Bio-Implant Applications

Newly Developed Quaternary Ti- and Fe-Based Thin Film Metallic Glasses for Potential Bio-Implant Applications

Selective laser melting manufactured porous Fe-based metallic glass matrix composite with remarkable catalytic activity and reusability

The ever-increasing environmental consciousness has stimulated new design of catalysts to meet environmental requirements due to rapid expansion of industrialization. Additive manufacturing now emerges as a novel technology that revolutionizes the way of material manufacturing with functional applications. Herein, the manufacturing of an Fe-based metallic glass (MG) matrix composite with three-dimensional rhombic dodecahedron microstructure by selective laser melting (SLM) is reported. The SLM-produced porous Fe-based MG matrix composite has been employed into catalytic activation in Fenton-like process and sulfate radical-based reaction. Results demonstrate that up to 45 times reusability is achieved in sulfate radical-based reaction without any apparent efficiency decay, which is the highest reusability with high efficiency by catalysts as of now. The remarkable catalytic reusability originates from extremely low surface decay in sulfate radical-based reaction. In addition, structural analysis indicates the α-Fe nanocrystals could trigger easy electron transfer but a large amount of α-Fe lead to an inhibitive catalytic effect in the MG matrix composite. The overall catalytic ability also demonstrates the excellent catalytic performance of SLM-produced porous Fe-based MG matrix composite in the wastewater remediation. This work suggests a novel SLM-produced catalyst with promising industrial potential and value.

Synergistic function of iron and cobalt in metallic glasses for highly improving persulfate activation in water treatment

Although metallic glasses (MGs) with unique disordered atomic structure have increasingly attracted great research interest as one of the most innovative heterogeneous catalysts in water remediation, few works focused on the synergistic role of different elemental constituents to well understand their superb catalytic performance. Herein, Co atoms were selected to partially substitute for the Fe elements in Fe-based MGs to study the corresponding synergistic catalytic function in dye degradation. Experimental results demonstrated that the Fe36Co36Si4.8B19.2Nb4 MG with a kinetic rate constant of k = 0.06 min−1 degrades rhodamine B (RhB) dye 20 times faster than the Fe73.5Si13.5B9Cu1Nb3 MGs with k = 0.003 min−1. Three types of dye including RhB, methylene blue (MB) and malachite green were investigated to draw attention to the broad, practical applications. Various chemical parameters, such as catalyst dosage, persulfate concentration, and dye concentration, were also studied. Quenching experiments indicated that the highly active hydroxyl (⋅OH) and sulfate (SO4⋅−) radicals are largely produced from persulfate by the activation of the Fe36Co36Si4.8B19.2Nb4 MG catalyst. This critical work uncovers a new paradigm to establish an effective approach for alloy design in widespread catalytic applications.

Effect of compositional elements and processing routes on structural and thermal response in Fe-based metallic glasses

The effect of varying thickness on structure and thermal properties is investigated in Fe–B–Nb and Fe–B–Si–Nb glassy alloy systems with the addition of different Nb and Co content, respectively. Accordingly, four alloys with the nominal compositions of Fe76-xB18Nb6+x (x = 0, 2) and (Fe1-yCoy)72B12Si12Nb4 (y = 0, 0.5) are processed in the forms of ribbon and rod. All alloys of ribbons represent amorphous structure, while those of rods explain the crystalline structure with the exception of heteromorphous structure for Co added alloy. The Nb addition causes about same glass transition temperature (Tg) but increases crystallization onset (Tx), resulting in a wider supercooled liquid region (ΔTx = Tx-Tg). Moreover, Nb also improves glass forming ability (GFA) with more free volume generation and higher structural relaxation exothermic heat (ΔH0). The Co addition also improves free volume generation and higher ΔH0 for ribbon, but lower amount free volume generation in bulk alloys (rod) than ribbon.

Mechanical properties and tribological behavior of aluminum matrix composites reinforced with Fe-based metallic glass particles: Influence of particle size

Aluminum matrix composites consisting of Al2024 and Fe-based metallic glass powders were prepared via powder metallurgy by using an optimized matrix to reinforcement particle size ratio, the influence of glassy particle size on mechanical properties and dry sliding wear behavior of the composites were investigated. The composites showed dense structure and homogenous three-dimensional distribution of the reinforcements independent of particle size. The particle size has negligible influence on yield strength, while ultimate tensile strength and ductility gradually decrease with increasing particle size. Reduced specific wear rate was observed when particle size increases, most likely because of the evolution of the surface topography during sliding where the wear of matrix is protected when particles are large.

Selective laser melting vitrification of amorphous soft magnetic alloys with help of double-scanning-induced compositional homogeneity

Recently, selective laser melting (SLM) of Fe-based soft magnetic bulk metallic glass (BMG) is garnering great attention because it can yield both superior magnetic properties such as high permeability and low core loss and near-net shaping of 3-dimensional complex components. However, full vitrification of BMGs with high saturation magnetization above 1.2 T has never been realized because cooling rates are limited and compositional inhomogeneity induced by rapid laser processing causes severe undesirable crystallization. In this work, a double scan strategy has been employed with the aim of amorphous phase fraction enhancement as well as densification. We have shown that double scanning effectively fills voids generated due to partial melting of powders, and leads to relative density of up to 96% and corresponding saturated magnetization of 1.22 T. More importantly, the double scan strategy stimulates reflow in the melt pool, securing compositional uniformity, and eventually enhances amorphous phase fraction to a value as high as 47%. As a consequence, coercivity has been significantly decreased, which in turn reduces core loss and increases permeability.