Properties Of Amorphous Alloys Research Articles

Analysis of icosahedral structure in rapidly solidified Pd<sub>82</sub>Si<sub>18</sub> amorphous alloy under high pressure

Compared with traditional glass, metallic glass (MG) has excellent properties, such as high strength, high hardness, high fracture toughness, good soft magnetic properties and corrosion resistance due to its unique structure. Such properties enable it to be used in optics, electronics, construction and other fields, making it a highly promising new material with great application potential. As the properties of amorphous alloys are closely linked with their local structures, microstructure characteristics have always been a research focus in the amorphous field. Previous studies show that the onset temperature of heredity and the hereditary fraction of characteristic clusters can be used to effectively evaluate the glass-forming ability. In order to obtain the relationship between the microstructure characteristic and cluster evolution of amorphous alloy, and reveal the formation of glass, the glass transition processes of the Pd<sub>82</sub>Si<sub>18</sub> alloy under different pressure conditions are simulated by using the molecular dynamics method, and the heredity and evolution of the Pd<sub>82</sub>Si<sub>18</sub> amorphous alloy are analyzed by using the cluster-type index method and the reverse tracking method. The simulation results show that the glass transition temperature of the Pd<sub>82</sub>Si<sub>18</sub> alloy can be increased when the pressure is higher, and a large number of icosahedra are formed in the solidified alloy when the pressure is sufficiently high. Icosahedron is a kind of structure that widely exists in amorphous materials and has been studied for quite a long time. In this work, a detailed comparative analysis of two icosahedra is conducted and the heritability of clusters with different chemical compositions under high pressure is studied. The results show that it is easier for icosahedra with central atom Pd and those with central atom Si to form a medium-range order in the Pd<sub>82</sub>Si<sub>18</sub> amorphous alloy. An increase in pressure conduces to the increase of both onset temperature of heredity and hereditary fraction. Combined with the results of cluster heredity analysis at 0 GPa, the Si-centered clusters have stronger heritability than Pd-centered clusters, thus the former ones have a greater influence on the glass-forming ability. These findings are of significance in understanding the relationship between microstructure evolution and glass formation, and also providing certain guidance for designing amorphous alloys.

Analysis of icosahedral structure in rapidly solidified Pd<sub>82</sub>Si<sub>18</sub> amorphous alloy under high pressure

Compared with traditional glass, metallic glass (MG) has excellent properties, such as high strength, high hardness, high fracture toughness, good soft magnetic properties and corrosion resistance due to its unique structure. Such properties enable it to be used in optics, electronics, construction and other fields, making it a highly promising new material with great application potential. As the properties of amorphous alloys are closely linked with their local structures, microstructure characteristics have always been a research focus in the amorphous field. Previous studies show that the onset temperature of heredity and hereditary fraction of characteristic clusters can be used to effectively evaluate the ability of an amorphous alloy to form glass. In order to obtain the relationship between the microstructure characteristic and cluster evolution of amorphous alloy, and reveal the formation of glass, the glass transition processes of the Pd<sub>82</sub>Si<sub>18</sub> alloy under different pressure conditions are simulated by using the molecular dynamics method, and the heredity and evolution of the Pd<sub>82</sub>Si<sub>18</sub> amorphous alloy are analyzed by using the cluster-type index method and the reverse tracking method. The simulation results show that the glass transition temperature of the Pd<sub>82</sub>Si<sub>18</sub> alloy can be increased when the pressure is higher, and a large number of icosahedra are formed in the solidified alloy when the pressure is sufficiently high. Icosahedron is a kind of structure that widely exists in amorphous materials and has been studied for quite a long time. In this work, a detailed comparative analysis on two icosahedra is conducted and the heritability of clusters with different chemical compositions under high pressure is studied. The results show that it is easier for icosahedra with central atom Pd and those with central atom Si to form a medium-range order in the Pd<sub>82</sub>Si<sub>18</sub> amorphous alloy. An increase in pressure conduces to the increasing of both onset temperature of heredity and hereditary fraction. Comparing with the results of cluster heredity analysis under 0 GPa, the Si-centered clusters have stronger heritability than Pd-centered clusters, thus the former ones have a greater influence on the ability to form glass. These findings are of significance in understanding the relationship between microstructure evolution and glass formation,and also providing certain guidance for designing amorphous alloys.

Enhanced mechanical properties of Zr-Cu-Al-Ni bulk amorphous alloys by Ag and O doping

The microstructure and properties of amorphous alloys are very sensitive to oxygen content, so the extremely stringent atmospheric condition is required for their production, which also significantly increases the production costs. In this work, the strength and plasticity of Zr52Cu23Ni10.5Al14.5 amorphous alloy rods with a diameter of 2 mm are severely deteriorated after the addition of 0.15 at% O due to the formation of micrometer scale crystalline phases in glassy matrix. In contrast, the combined addition of 1 at% Ag and 0.15 at% O can substantially improve its fracture strength and plasticity. This synergy effect is mainly attributed to the fact that minor Ag addition can enhance the uniform distribution of nanocrystalline phases and refine their sizes. The present results can provide ideas for the industrial production and large-scale commercial applications of amorphous alloys in the future.

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.

Effect of Minority Alloying Elements Zn and Zr on the Mechanical Properties of Amorphous Alloys АlCuMg(Zn) and AlCuMg(Zr) and their Nanocrystalline Analogues

Effect of Minority Alloying Elements Zn and Zr on the Mechanical Properties of Amorphous Alloys АlCuMg(Zn) and AlCuMg(Zr) and their Nanocrystalline Analogues

Construction and Research of Amorphous Alloys and Ferroelectric Materials in the Digital Logistics Platform

People have higher and higher requirements for the size, sensitivity, measurement range, repeatability error, and power consumption cost of sensors and memories in the field of electronic information technology. “Logistics” as another new industry in the modern social division of labor is showing its infinite vitality, and the rise of digital logistics is the use of network technology to meet the development of this era. Based on the application of amorphous alloys and ferroelectric materials to the construction of logistics digital platform, this paper is aimed at demonstrating the function of nonstatic alloys and ferroelectric materials to promote the data storage of logistics digital platform and other aspects from multiple perspectives. This article is mainly divided into two general directions. The first is to study the physical and chemical properties of amorphous alloys and ferroelectric materials separately. The content of the article is more complete by referring to relevant research literature or obtaining relevant targeted information; the basic structure of the digital logistics platform is modeled, and the application of amorphous alloys and ferroelectric materials is mainly applied to the two parts of the data service composition and the data layer. This arrangement is based on the sensor as the key to data processing. Location is of great significance to the entire platform system. The experimental results show that the digital logistics platform constructed in this paper can reach a score of 7.75 in terms of data security and 7.39 in terms of flexibility. It also increases the efficiency of the entire operation process.

Effect of Mn Substitution Fe on the Formability and Magnetic Properties of Amorphous Fe88Zr8B4 Alloy

Elemental substitution is commonly used to improve the formability of metallic glasses and the properties of amorphous alloys over a wide compositional range. Therefore, it is essential to investigate the influence of element content change on the formability as well as magnetic and other properties. The purpose is to achieve tailorable properties in these alloys with enhanced glass forming ability. In this work, the glass-forming ability (GFA) and magnetic properties of the minor Mn-substituted Fe88Zr8B4 amorphous alloy were investigated. The addition of Mn improving the amorphous forming ability of the alloy. With the addition of Mn, the magnetic transition temperature, saturation magnetization and the magnetic entropy changes (−ΔSm) peaks decreased simultaneously, which is possibly caused by the antiferromagnetic coupling between Fe and Mn atoms. The dependence of −ΔSmpeak on Tc displays a positive correlation compared to the −ΔSmpeak- Tc−2/3 relationship proposed by Belo et al.

Evolution of defect concentration in Zr<sub>50–</sub><i><sub>x</sub></i>Cu<sub>34</sub>Ag<sub>8</sub>Al<sub>8</sub>Pd<i><sub>x</sub></i> (<i>x</i> = 0, 2) amorphous alloys derived using shear modulus and calorimetric data

Amorphous alloys exhibit unique physical and mechanical properties, which are closely connected with their microstructural heterogeneity. The correlation between structural heterogeneity and mechanical properties is one of the important issues of amorphous alloys. Micro-alloying is an effective way to tune the mechanical and physical properties of amorphous alloys. In the present study, Zr<sub>50–</sub><i><sub>x</sub></i>Cu<sub>34</sub>Ag<sub>8</sub>Al<sub>8</sub>Pd<i><sub>x</sub></i> (<i>x</i> = 0 and 2) amorphous alloys with ability to form excellent glass are chosen as model alloys. The evolutions of heat flow and shear modulus in different states (as-cast, relaxed and crystalline) with temperature of Zr<sub>50–</sub><i><sub>x</sub></i>Cu<sub>34</sub>Ag<sub>8</sub>Al<sub>8</sub>Pd<i><sub>x</sub></i> (<i>x</i> = 0 and 2) glass system are studied by differential scanning calorimetry (DSC) and electromagnetic-acoustic transformation (EMAT) technique, respectively. The experiment demonstrates that a decrease of the shear modulus is accompanied by the endothermic heat flow and vice versa. The correlation between the heat flow and shear modulus is investigated according to the interstitialcy theory. The calculations of the interstitialcy defect concentration and activation energy spectra suggest that the microstructure remains stable at relatively low temperatures. When temperature increases, the interstitialcy defect structure is activated. Compared with that in the as-cast state, the interstitialcy defect concentration in the relaxed state is reduced by structural relaxation, indicating that temperature-dependent shear modulus softening is inhibited. At temperatures above glass transition temperature, a rapid growth of interstitialcy defect concentration results in the accelerated shear softening, which is accompanied by significant endothermic heat flow. It is noted that the minor addition of palladium reduces the interstitialcy defect concentration in the Zr<sub>50–</sub><i><sub>x</sub></i>Cu<sub>34</sub>Ag<sub>8</sub>Al<sub>8</sub>Pd<i><sub>x</sub></i> (<i>x</i> = 0 and 2) metallic glass systems. It is suggested that the introduction of Pd reduces the atomic mobility and increases the characteristic relaxation time. In parallel, the change of shear modulus as a function of the aging time (below the glass transition temperature) is studied by using EMAT equipment. The results indicate that the interstitialcy defect concentration decreases in the physical aging process, which is accompanied by an increase of shear modulus. The interstitialcy defect concentration and shear modulus change towards the quasi-equilibrium state with aging time increasing. A reduction of the interstitialcy defect concentration leads to a decrease of the shear modulus change upon microalloying by Pd into Zr<sub>50–</sub><i><sub>x</sub></i> Cu<sub>34</sub>Ag<sub>8</sub>Al<sub>8</sub>Pd<i><sub>x</sub></i> (<i>x</i> = 0 and 2) metallic glass system.

Structures and Functional Properties of Amorphous Alloys

Amorphous alloys have attracted great attention due to their distinctive properties derived from unique packing structures. Recently, significant advances have been achieved for the understanding of structural characteristics and functional applications of amorphous alloys. Herein, an overview of the state of art of structure studies, accounting for the characteristics of amorphous alloys, are presented, and recent progresses in the functional applications of amorphous alloys are highlighted. The various structural models for the short‐range order, medium‐range order, and long‐range topological order for amorphous alloys are introduced. The functional applications in electrochemistry, mechanism, magnetism, optics, and biomedical engineering are presented in detail. The fundamental understanding of the correlations between structures and properties in amorphous alloys is discussed.

The impact of nanoscale compositional variation on the properties of amorphous alloys

The atomic distribution in amorphous FeZr alloys is found to be close to random, nevertheless, the composition can not be viewed as being homogenous at the nm-scale. The spatial variation of the local composition is identified as the root of the unusual magnetic properties in amorphous hbox {Fe}_{1-x}hbox {Zr}_{x} alloys. The findings are discussed and generalised with respect to the physical properties of amorphous and crystalline materials.

Influence of HPT Deformation on the Structure and Properties of Amorphous Alloys

Recent studies showed that structural changes in amorphous alloys under high pressure torsion (HPT) are determined by their chemical composition and processing regimes. For example, HPT treatment of some amorphous alloys leads to their nanocrystallization; in other alloys, nanocrystallization was not observed, but structural transformations of the amorphous phase were revealed. HPT processing resulted in its modification by introducing interfaces due to the formation of shear bands. In this case, the alloys after HPT processing remained amorphous, but a cluster-type structure was formed. The origin of the observed changes in the structure and properties of amorphous alloys is associated with the chemical separation and evolution of free volume in the amorphous phase due to the formation of a high density of interfaces as a result of HPT processing. Amorphous metal alloys with a nanocluster structure and nanoscale inhomogeneities, representatives of which are nanoglasses, significantly differ in their physical and mechanical properties from conventional amorphous materials. The results presented in this review show that the severe plastic deformation (SPD) processing can be one of the efficient ways for producing a nanocluster structure and improving the properties of amorphous alloys.

Effect of Laser Radiation on the Structure and Properties of Amorphous Alloys: A Review

A brief review is performed of scientific works on the current state of research on the crystallization of rapidly quenched amorphous alloys under the action of laser radiation, along with their structural transformations and changes in their physical and mechanical properties after laser treatment.

ВЛИЯНИЕ ТЕРМИЧЕСКОЙ ОБРАБОТКИ НА СВОЙСТВА АМОРФНОГО СПЛАВА НА ОСНОВЕ КОБАЛЬТА

ВЛИЯНИЕ ТЕРМИЧЕСКОЙ ОБРАБОТКИ НА СВОЙСТВА АМОРФНОГО СПЛАВА НА ОСНОВЕ КОБАЛЬТА

The formation of hysteretic magnetic properties in amorphous alloys of various classes upon thermomagmetic treatment in a transverse magnetic field

In this paper, we have studied the effects of the thermomagnetic treatment in a transverse magnetic field (TMaT⊥) on the permeability of the amorphous alloy Co69Fe3.7Cr3.8Si12.5B11 with such a low saturation magnetostriction (λs 10–7) that, in the ribbons of this alloy rolled into a toroid, a sharp longitudinal magnetic texture is observed (Ksq > 0.90). It has been revealed that the permeability μ4 (H = 4 mOe, f = 1 kHz) as a function of the annealing temperature or time of holding at a temperature is described by a curve with a maximum. This maximum is observed at a coefficient of the squareness of the hysteresis loop Ksq,m in the range of 0.2 ≤ Ksq,m ≤ 0.4. The regimes of the TMaT have been determined that provide optimum values of the permeability μ4 (15000) without a loss of the ductile state of the ribbons of this alloy. Based on the example of an iron-based alloy of composition Fe57Co31Si2.9B9.1 with λs = 35 × 10–6, it has been shown that the formation of the hysteretic magnetic properties upon the TMaT⊥ depends substantially on the magnitude of the magnetostriction and the Curie temperature of the amorphous alloys.

Influence of Annealing Treatment on Microstructure and Mechanical Properties of Fe-Cu-Si-Al Amorphous Composites

In this study, the bulk amorphous alloys with 3mm in diameter were prepared at different voltages adopting copper mould suction casting method by adding microelement Al to Fe-Cu-Si based amorphous alloy respectively. The microstructures, glass-forming ability, mechanical compressive properties of (Fe0.34Cu0.47Si0.19)95Al5 amorphous composites annealed in different temperature were investigated. The results showed that re-melting of master alloy refined the solidified microstructure and homogenize the composition and microstructure. Moreover, the microstructure was stable with the increase of re-melting times. After relaxation and annealing at low temperature the majority of residual thermal stress was released during annealing at low temperature, with the enlargement of short-range order of amorphous microstructure and the decrease of the most adjacent inter-atomic distance. After proper annealing treatment the hardness and thermal stability of alloy were improved, indicating that the annealing treatment could improve the properties of amorphous alloy.

Effect of annealing on the structural and magnetic properties of (Fe1−xCox)83B17 metallic glasses

Abstract Amorphous alloys of (Fe 1− x Co x ) 83 B 17 ( x =22, 25.3, 28.4) in the vicinity of 25 at% of Co were prepared by melt spun technique. The samples were annealed at different temperatures and the changes in structural and magnetic properties have been studied. Phase stabilization and magnetic properties of amorphous alloys were studies using X-ray diffraction and Mossbauer spectroscopy. The result shows anomalies in structure and in magnetic properties in the studied samples. Annealing at 475 °C brings about the formation of complete and stable crystalline structure. At this stage multiple crystalline phases have been observed. Mossbauer spectroscopy also revealed that two phases of Fe 3 B were formed along with stable Fe 3 Co phase.

Effect of Thermobaric Treatment on the Nanoporosity and Properties of Amorphous Alloys

Effect of Thermobaric Treatment on the Nanoporosity and Properties of Amorphous Alloys

Influence of Annealing on the Microstructure and Magnetic Properties in Amorphous Alloys

Abstract The influence of isothermal annealing on the magnetisation process in strong magnetic fields of the amorphous Fe61Co10Y8Ni1B20 alloy ribbons was investigated. Samples in the form of ribbons were produced by rapid quenching of liquid alloy on a rotating copper wheel. In order to study the relaxation process, the investigated Fe61Co10Y8Ni1B20 samples were subjected to annealing below the crystallisation temperature at 700 K for 1 h and then at 770 K for 3.5 h. The structure of the samples was examined by X-ray diffraction measurements (XRD). It was found, that all of measured samples in the as-cast state and after thermal treatment, were amorphous. On the basis of virgin magnetisation curve analysis, the type, size and density of structural defects occurring in the investigated samples were determined. It was found that after the first stage of annealing, decay of linear defects (pseudo-dislocation dipoles) into smaller, more thermodynamically stable, point defects occurs. The presence of point like defects was also confirmed after the second stage of annealing.

Magnetoelastic effects in amorphous alloys

The domain structure and properties of amorphous ferromagnetic alloys are studied. The magnetic properties of amorphous alloys may be effectively regulated by creating a specific quasi-structure based on magnetoelastic effects.

Structure and tribological properties of amorphous alloys based on iron and nickel

The structure and tribological properties of amorphous layers based on iron and nickel are studied. Significant differences in the wear rate of amorphous foils of various alloys are revealed at the initial test stages. The incubation period on the wear curve of the Fe-Ni-Si-B alloy points to some peculiarities of the structural phase transitions in the surface layers of the foil of the alloy during friction. Due to high alloying of Fe-Ni-Si-B the kinetics of its crystallization during friction is slower than in the Fe-B alloy.