Glassy Alloys Research Articles

Optical transmission, dielectric constants, and gamma shielding performance of Se95-xIn5Prx metallic alloys: Radiation protection applications

Due to the high density of metals, metallic materials such as alloys have the potential to have high gamma-radiation-absorbing abilities. This would make them relevant in a radiation environment as either a shielding material or a radiation sensor. These would, however, depend on their gamma radiation responses. Research aimed at evaluating the gamma response parameters of different glassy alloys that have technical applications is scarce compared to the traditional characterization with respect to optical features, structural evolution, and mechanical strength. In this paper, the optical and radiation shielding abilities of Se95-xIn5Prx (x = 2, 4, and 6) glassy alloys were investigated using standard theoretical techniques. The mass attenuation coefficient (MAC) of the materials was computed using the XCOM software. Reflection loss values are 0.20218, 0.22634, and 0.22908 for SIPr1, SIPr2, and SIPr3, respectively, while the optical transmittance values are 0.66365, 0.63087, and 0.62723 in the same order. The metallization criterion declined when Pr increased in the alloy. The values of MAC ranged from 0.0317 cm2/g to 98.2099 cm2/g for SIPr1, 0.0319 cm2/g to 97.3798 cm2/g for SIPr2 and 0.0322 cm2/g to 96.5372 cm2/g for SIPr3. The Higher attenuation and absorption coefficients were found for Pr-rich alloys. Pr therefore increase the ability of the SIPr-alloy to attenuate and absorb photon energy. The optical parameters of the investigated alloys could be used to identify their optical applications. SIPr3 had comparatively higher shielding ability compared to some known shields and could thus be used for radiation control and protection purposes.

Design and development of large-diameter Mg-Zn-Ca bulk metallic glass for biomedical applications: A mechanical and corrosion perspective

Being amorphous, bulk metallic glasses (BMGs) exhibit superior properties compared to their crystalline alloy counterparts. Amorphous materials are preferred for their excellent mechanical and degradation behavior. Among the various elemental combinations, MgZnCa has shown the most promising results, as evidenced by the literature. However, the maximum achievable size of the metallic glasses remains a bottleneck. The current work aims to address this challenge and achieve it splendidly with a systematic methodology by developing larger diameter MgZnCa BMGs through vacuum induction casting using a specially designed copper mold. The optimal composition was formalized for glass formation of the Mg65Zn31Ca4 system using the CALPHAD technique. As a result, a 6.5 mm diameter glassy alloy was successfully obtained. The XRD and TEM analysis experiments demonstrated a perfect amorphous structure of the developed sample. The anti-corrosion properties of the as-cast glass increased, followed by enhancement in the yield strength and hardness in contrast to the properties of the human bone. Furthermore, the surface wettability analysis showed an adequate surface obtained to promote fibroblast adhesion. In conclusion, the current work represents a notable progress in the fabrication of larger-diameter MgZnCa BMG for biomedical applications, considering that the biggest diameter ever reported in the MgZnCa system was more than a decade ago.

Experimental investigation of comprehensive performance by tailoring the proportion of late transition metals in quinary Fe-Co-Ni-Si-B amorphous alloys

We fabricated the Fe-Co-Ni-Si-B multi-principal element alloys by vacuum melt-spinning method. The effects of late transition metals proportion in quinary alloy ribbons on the formation, phase structure, thermal stability, microhardness, corrosion resistance and soft magnetic properties were investigated. The melt-spun structure consists of an amorphous single phase for all the specimens. The surfaces of glassy ribbons are rather flat and flawless and the average surface roughness is 0.351 nm or below. The initial crystallization temperature (Tx) and supercooled liquid region (ΔTx) of alloy system decrease by degrees with increasing Co and Ni content, showing the maximum values of 753.0 K and 60.0 K for Fe60Co10Ni10Si6B14 alloy. But the glass transition temperature (Tg) seems to barely change and maintain approximately 692.0 K. All the as-received alloy ribbons exhibit good bending ductility and acceptable Vickers microhardness ranging from 671 to 785 HV0.5. The amorphous alloy ribbons present a gradually wide passive potential range (ΔE) with the decrease of Fe content, but the corrosion current density (Icorr) becomes larger. The smallest Icorr value is 1.785 μA·cm-2 for Fe60Co10Ni10Si6B14 alloy and the widest ΔE value is about 0.272 V for Fe26Co27Ni27Si6B14 alloy. The saturation magnetization of these glassy alloys reduces from 165.0 to 112.0 emu/g as the Fe content decreases. Meanwhile, the coercivity also changes from 14.25 to 6.70 A/m. This paper offers a brand-new perspective to understand the role of late transition metals on the various physicochemical properties of quinary Fe-Co-Ni-Si-B amorphous alloys.

Molecular-Network Transformations in Tetra-Arsenic Triselenide Glassy Alloys Tuned within Nanomilling Platform.

Polyamorphic transformations driven by high-energy mechanical ball milling (nanomilling) are recognized in a melt-quenched glassy alloy of tetra-arsenic triselenide (As4Se3). We employed XRPD analysis complemented by thermophysical heat-transfer and micro-Raman spectroscopy studies. A straightforward interpretation of the medium-range structural response to milling-driven reamorphization is developed within a modified microcrystalline model by treating diffuse peak-halos in the XRPD patterns of this alloy as a superposition of the Bragg-diffraction contribution from inter-planar correlations, which are supplemented by the Ehrenfest-diffraction contribution from inter-atomic and/or inter-molecular correlations related to derivatives of thioarsenide As4Sen molecules, mainly dimorphite-type As4Se3 ones. These cage molecules are merely destroyed under milling, facilitating the formation of a polymerized network with enhanced calorimetric heat-transfer responses. Disruption of intermediate-range ordering, due to weakening of the FSDP (the first sharp diffraction peak), accompanied by an enhancement of extended-range ordering, due to fragmentation of structural entities responsible for the SSDP (the second sharp diffraction peak), occurs as an interplay between medium-range structural levels in the reamorphized As4Se3 glass alloy. Nanomilling-driven destruction of thioarsenide As4Sen molecules followed by incorporation of their remnants into a glassy network is proved by micro-Raman spectroscopy. Microstructure scenarios of the molecular-to-network polyamorphic transformations caused by the decomposition of the As4Se3 molecules and their direct destruction under grinding are recognized by an ab initio quantum-chemical cluster-modeling algorithm.

Comparative study of physical properties of As2Se3 and (As2Se3)90Ge10 glassy alloys doped with metallic impurities

To examine the compositional and chemical effects on the glassy system, one must first understand its network structure. Alloying glassy systems cause significant conformal and configurational changes. The optical and physical parameters of As2Se3 and (As2Se3)90Ge10 glassy alloys doped with metallic impurities (X = Bi, Cd, Pb, Sb) have been evaluated. A comparison of the physical properties of glassy alloys has been made as the doping elements increase, i.e., from binary to ternary to quaternary system, and an effort has been made to correlate the optical and physical parameters. The optical density (Dop) and penetration depth (δ) have been calculated from the reported absorption coefficient (α) data. The mean coordination number (<r>) and the number of floppy modes (Mf) calculations show that the floppy regions are decreasing, and hence, the rigidity is increasing when As–Se is doped with Ge and As–Se-Ge is doped with X. The density (ρ) and packing density (PD) have also been evaluated, which are interrelated to the parameters like refractive index (n) and δ. Cohesive energy (CE), mean bond energy (<E>), and glass transition temperature (Tg) values give an insight into the stability and average crosslinking of the system with alloying. The conduction and valence band potentials have supported the optical bandgap (Egopt) values variation.

The role of Cr in optimizing properties of Fe–B–C–P–Si–Mo–Cr metallic glasses for applications

With the rapid development of third-generation semiconductors, there is an urgent need to develop high-performance soft magnetic Fe-based metallic glasses tailored particularly for their high-frequency applications. In this work, new Fe76−yB7C7P7Si3Moy−xCrx (y = 0, 1, 2, 3 at.%, x ≤ y) alloys with relatively high glass-forming ability (GFA) were developed. The effects of replacing Mo with Cr on GFA, thermodynamic properties, soft magnetic properties, electrical resistivity (ρ), and corrosion resistance at different Fe contents were systematically studied. The possible causes of GFA variation were discussed. The results show that the addition of a small amount of Cr replacing Mo under different Fe contents would not lead to a decrease in GFA. The critical sizes of Cr-containing glassy alloys are 1–2.5 mm. These alloys possess relatively high saturation magnetization (Ms) of 1.29–1.41 T and lower coercivity (Hc) of 0.7–1.8 A/m, contributing to the reduction of hysteresis loss. In addition, Cr increases ρ of the alloys, reaching up to 162 μΩ cm, which is beneficial to reducing eddy current loss at high frequency. Furthermore, Cr effectively enhances corrosion resistance, thereby increasing the service life of the alloys in harsh environments. The role of Cr in these aspects makes it a beneficial element in soft magnetic metallic glasses for high-frequency applications.

Room-temperature pressure-induced phase separation in glassy alloys

Understanding the structural evolution of glass-forming alloys (metallic glasses) under high pressure conditions is important, on one hand, for elucidating their phase stability, and on the other, for manipulating their structure and properties. In this study, we investigate the unique pressure-induced effect leading to the phase separation phenomenon in glassy alloys, the effect which was not observed in the earlier works. By subjecting the system to various levels of external isostatic pressure, we observed the emergence of a distinct phase-separated structure within some glassy alloys. Our results shed light on the underlying mechanisms of phase separation in glassy alloys under extreme pressure conditions, providing valuable information for possible control of their structure and properties. This demonstrates that pressure can be used along or instead of temperature to produce nano-structured polyphase metallic glasses.

Enhanced Corrosion Resistance in High-Strength Biodegradable Mg-Zn-Ca-Si Glassy Alloy Composite via Preparation of a Self-Sealing Plasma Electrolytic Oxidation Layer

Enhanced Corrosion Resistance in High-Strength Biodegradable Mg-Zn-Ca-Si Glassy Alloy Composite via Preparation of a Self-Sealing Plasma Electrolytic Oxidation Layer

Plastic quasicrystal-containing alloys prepared by annealing pseudo-high entropy Zr70–75(Al, Ni, Cu, Ag)25–30 glassy alloys

A glassy (G) phase was formed for Zr-rich Zr70–75(Al, Ni, Cu, Ag)25–30 (atomic percent, at.%) melt-spun alloy ribbons. These glassy alloys exhibit the glass transition, followed by a supercooled liquid region and then three-stage crystallization. The glass transition temperature and the onset temperature for the first-stage crystallization (Tx1) decrease from 630 to 668 K, respectively for the 70Zr alloy to 619 and 652 K, respectively for the 75Zr alloy. The first-stage exothermic peak is due to the precipitation of an icosahedral quasicrystal (IQ) phase. The IQ particle size decreases from 10 nm to 6 nm with increasing Zr content from 70at.% to 74at.%. The [G + IQ] phases change to Zr2Ni + Zr2(Cu, Ag) phases after the second exothermic peak and then Zr2Ni + Zr2(Cu, Ag) + Zr5Al3 phases after the third stage. It is noticed that the as-spun glassy alloy ribbons as well as the annealed [G + IQ] phase ribbons exhibit good bending plasticity. Furthermore, the 70Zr thicker ribbons also exhibit high tensile fracture strength of 1090–1187 MPa and plastic elongation of 0.17 %–0.42 %. The fracture mode is similar to that of ordinary bulk metallic glasses. The Vickers hardness (Hv) is 480 for 70Zr alloy and decreases to 436 for 75Zr alloy. The precipitation of IQ phase causes a significant increase in Hv to about 554. The formations of glassy alloys with high Zr contents of 70at.%–75at.% by melt spinning as well as the [G + IQ] phase alloys with good bending plasticity by annealing hold promise for the creation of a new type of engineering material, transcending mere academic novelty.

Electrochemical Surface Nanostructuring of Ti47Cu38Fe2.5Zr7.5Sn2Si1Ag2 Metallic Glass for Improved Pitting Corrosion Resistance

Ti‐based bulk metallic glasses are envisioned for human implant applications. Yet, while their elevated Cu content is essential for a high glass‐forming ability, it poses biocompatibility issues, necessitating a reduction in near‐surface regions. To address this, surface treatments that simultaneously generate protective and bioactive states, based on nanostructured Ti and Zr‐oxide layers are proposed. An electrochemical pseudo‐dealloying process using the bulk glass‐forming Ti47Cu38Fe2.5Zr7.5Sn2Si1Ag2 alloy is defined. Melt‐spun ribbons are immersed in hot concentrated nitric acid solution, monitoring the anodic polarization behavior. From the current density transient measurements, together with surface studies (field‐emission scanning electron microscopy, transmission electron microscopy, and Auger electron spectroscopy), the surface reactions are described. This nanostructuring process is divided into three stages: passivation, Cu dissolution, and slow oxide growth, leading to homogenous nanoporous and ligament structures. By tuning the applied potential, the pore and ligament sizes, and thickness values are adjusted. According to X‐ray photoelectron spectroscopy, these nanoporous structures are Ti and Zr‐oxides rich in hydrous and nonhydrous states. In a simulated physiological solution, for those treated glassy alloy samples, complete suppression of chloride‐induced pitting corrosion in the anodic regime of water stability is achieved. This high corrosion resistance is similar to that of clinically used cp‐Ti.

Revealing in situ stress-induced short- and medium-range atomic structure evolution in a multicomponent metallic glassy alloy

Deformation behaviour of multicomponent metallic glasses are determined by the evolution/reconfiguration of the short- and medium-range order (SRO and MRO) atomic structures. A precise understanding of how different atom species rearrange themselves in different stress states is still a great challenge in materials science and engineering. Here, we report a systematic and synergetic research of using electron microscopy imaging, synchrotron X-ray total scattering plus empirical potential structure refinement (EPSR) modelling to study in situ the deformation of a Zr-based multicomponent metallic glassy alloy with 5 elements. Systematic and comprehensive analyses on the characteristics of the SRO and MRO structures in 3D and the decoupled 15 partial PDFs at each stress level reveal quantitatively how the SRO and MRO structures evolve or reconfigure in 3D space in the tensile and compressive stress states. The results show that the Zr-centred atom clusters have low degree of icosahedra and are the preferred atom clusters to rearrange themselves under the tensile and compressive stresses. The Zr-Zr is the dominant atom pair in controlling the shear band's initiation and propagation. The evolution and reconfiguration of the MRO clusters under different stress states are realised by changing the connection modes between the Zr-centred atom clusters. The coordinated changes of both bond angles and bond lengths of the Zr-centred clusters are the dominant factors in accommodating the tensile or compressive strains. While other solute-centred MRO clusters only play minor roles in the atomic structure reconfiguration/evolution. The research has demonstrated a synergetic and multimodal materials operando characterization methodology that has great application potential in design and development of high performance multiple-component engineering alloys.

Thermal Stability and Crystallization Processes of Pd78Au4Si18 Thin Films Visualized via In Situ TEM.

Amorphous alloys or metallic glasses (MGs) thin films have attracted extensive attention in various fields due to their unique functional properties. Here, we use in situ heating transmission electron microscopy (TEM) to investigate the thermal stability and crystallization behavior of Pd-Au-Si thin films prepared by a pulsed laser deposition (PLD) method. Upon heating treatment inside a TEM, we trace the structural changes in the Pd-Au-Si thin films through directly recording high-resolution images and diffraction patterns at different temperatures. TEM observations reveal that the Pd-Au-Si thin films started to nucleate with small crystalline embryos uniformly distributed in the glassy matrix upon approaching the glass transition temperature Tg=625K, and subsequently, the growth of crystalline nuclei into sub-10 nm Pd-Si nanocrystals commenced. Upon further increasing the temperature to 673K, the thin films transformed to micro-sized patches of stacking-faulty lamellae that further crystallized into Pd9Si2 and Pd3Si intermetallic compounds. Interestingly, with prolonged thermal heating at elevated temperatures, the Pd9Si2 transformed to Pd3Si. Simultaneously, the solute Au atoms initially dissolved in glassy alloys and eventually precipitated out of the Pd9Si2 and Pd3Si intermetallics, forming nearly spherical Au nanocrystals. Our TEM results reveal the unique thermal stability and crystallization processes of the PLD-prepared Pd-Au-Si thin films as well as demonstrate a possibility of producing a large quantity of pure nanocrystals out of amorphous solids for various applications.

Exploration of electrode-modulated memory and threshold switching behaviour in Se-Te-Sn thin film devices

Due to their potential use in high-density, three-dimensional stackable cross-point array structures, the electrical switching ability of chalcogenide glasses has captured a lot of attention. Herein, the switching behaviour of unique Se86-xTe14Snx (x = 0, 2, 4, 6) chalcogenide glassy alloys in the form of a thin film were investigated. The electrode modulated dual functionality in switching was achieved by employing Aluminium (Al) and Silver (Ag), as top electrodes. The films with Al/Se86-xTe14Snx/Al interface exhibited memory-type switching due to the phase-changing properties of the material. The threshold voltage (Vth) decreased linearly from 12.75 V to 4.2 V at room temperature as Sn concentration in the glass increased. On the other hand, when the top electrode was replaced with Ag, the Ag/Se86-xTe14Snx/Al interface acted as a programmable metallization cell (PMC) showing threshold-switching properties. Ag/Se82Te14Sn4/Al thin film of thickness 200 nm showed promising results as a material for a unidirectional selector, due to the formation of temporary Ag filament inside chalcogenide material. The composition showed high selectivity (∼104), high endurance (>104 cycles), and low threshold voltage (∼1.6 V). The ability of the composition to exhibit electrode-dependent memory and threshold-switching phenomena makes the material an interesting case.

Insight on the optoelectronic properties of novel quaternary Ge–Se–Tl–Sb non-crystalline glassy alloy films for optical fiber sensing devices

Chalcogenide glass (Ge0.1Se0.7Tl0.2)85Sb15 is synthesized in bulk form by the melt quenching method and thermally evaporated as thin films. The amorphous character of the studied films is examined by XRD analysis. The values of refractive index (n\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$n$$\\end{document}) and extinction index (k\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$k$$\\end{document}) are estimated from transmittance T(λ)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$T(\\lambda )$$\\end{document} data using Swanepoel’s method and are found to be thickness independent. The values of the indirect optical band gap (Egopt\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${E}_{g}^{{\ ext{opt}}}$$\\end{document}) and Urbach tail (EU\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${E}_{{\ ext{U}}}$$\\end{document}) energies are 1.164 eV and 0.176 eV, respectively. The optical σopt\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\sigma }_{{\ ext{opt}}}$$\\end{document} and electrical σelec\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\sigma }_{{\ ext{elec}}}$$\\end{document} conductivities of (Ge0.1Se0.7Tl0.2)85Sb15 films increase while the penetration depth Pd\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${P}_{{\ ext{d}}}$$\\end{document} decreases with photon energy (hν\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$h\ u$$\\end{document}). The Wemple-DiDomenico (WDD) oscillator model calculates optical parameters such as single-oscillator Eo\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${E}_{{\ ext{o}}}$$\\end{document} and strength Ed\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${E}_{{\ ext{d}}}$$\\end{document} energies, lattice dielectric constant εL\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\varepsilon }_{{\ ext{L}}}$$\\end{document} and ratio N/m∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{N}}/{{\ ext{m}}}^{*}$$\\end{document}. The calculated values of third-order susceptibility χ(3)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\chi }^{(3)}$$\\end{document} and nonlinear index of refraction n2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${n}_{2}$$\\end{document} are 6.34 × 10–12 and 3.76 × 10–11 esu\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{esu}}$$\\end{document}. Dielectric constant ε′\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\varepsilon }^{\\prime}$$\\end{document} and loss ε′′\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\varepsilon }^{{\\prime}{\\prime}}$$\\end{document} decrement with frequency and increment with temperature. The ac conductivity σac\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\sigma }_{{\ ext{ac}}}$$\\end{document} increases with frequency and temperature, which is proportional to ωs\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\omega }^{s}$$\\end{document} and the exponent s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$s$$\\end{document} decreases with temperature. The obtained results of σac\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\sigma }_{{\ ext{ac}}}$$\\end{document} and s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$s$$\\end{document} are interpreted via the correlated barrier hopping (CBH) model. Values of the density of localized states NEF\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$N\\left({E}_{{\ ext{F}}}\\right)$$\\end{document} are enhanced with frequency and temperature. The results obtained suggest that ε′\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\varepsilon }^{\\prime}$$\\end{document}, ε′′\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\varepsilon }^{{\\prime}{\\prime}}$$\\end{document}, σac\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\sigma }_{{\ ext{ac}}}$$\\end{document} and NEF\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$N\\left({E}_{{\ ext{F}}}\\right)$$\\end{document} are improved by decreasing the film thickness. These research results emphasize the composition’s applicability for several optical potential applications, like optical fiber sensing devices, photo-detectors, and narrow band optical filters.

An investigation of structural, thermo-physical, and photoelectric properties of glassy As2Se3–Tl2Te3alloys

Glass formation and the nature of the chemical interaction in the As2Se3–Tl2Te3system were studied by differential-thermal (DTA), X-ray phase (XRD), microstructural (MSA) analysis. Based on the performed experiments T-x phase diagram is constructed. It is established that the phase diagram of the system is a partially quasi-binary section of the quaternary system Tl,As//Se,Te. Eutectic equilibrium and peritectic transformation process occur in the system. When the ratio of As2Se3and Tl2Te3components is 1:1, a new quaternary compound Tl2As2Se3Te3is formed. It has been established that the Tl2As2Se3Te3compound melts with an open maximum at 568[Formula: see text]K and crystallizes in a hexagonal symmetry. In the system, under normal cooling, the glass formation area reaches −80[Formula: see text]mol.% Tl2Te3, and in the mode of quenching in liquid nitrogen up to −100[Formula: see text]mol.% T12Te3. The photoelectric properties of glassy alloys (As2Se[Formula: see text](Tl2Te[Formula: see text] ([Formula: see text]; 0.3; 0.05) have been studied. Depending on the Tl2Te3concentration of the system, the observed changes in the photoelectric properties and calculated parameters are presented.

Acid Treatments of Ti-Based Metallic Glasses for Improving Corrosion Resistance in Implant Applications

Ti-based bulk metallic glasses are promising materials for metallic bone implants, mainly due to their mechanical biofunctionality. A major drawback is their limited corrosion resistance, with high sensitivity to pitting. Thus, effective surface treatments for these alloys must be developed. This work investigates the electrochemical treatment feasibility of nitric acid (HNO3) solution for two bulk glass-forming alloys. The surface states obtained at different anodic potentials are characterized with electron microscopy and Auger electron spectroscopy. The corrosion behavior of the treated glassy alloys is analyzed via comparison to non-treated states in phosphate-buffered saline solution (PBS) at 37 °C. For the glassy Ti47Zr7.5Cu38Fe2.5Sn2Si1Ag2 alloy, the pre-treatment causes pseudo-dealloying, with a transformation from naturally passivated surfaces to Ti- and Zr-oxide nanoporous layers and Cu-species removal from the near-surface regions. This results in effective suppression of chloride-induced pitting in PBS. The glassy Ti40Zr10Cu34Pd14Sn2 alloy shows lower free corrosion activity in HNO3 and PBS due to Pd stabilizing its strong passivity. However, this alloy undergoes pitting under anodic conditions. Surface pre-treatment results in Cu depletion but causes enrichment of Pd species and non-homogeneous surface oxidation. Therefore, for this glassy alloy, pitting cannot be completely inhibited in PBS. Concluding, anodic treatments in HNO3 are more suitable for Pd-free glassy Ti-based alloys.

Effect of acid proticity on the thermodynamic parameters of charge transfer resistance in corrosion and passivation of nickel based glass alloy

The effect of temperature on electrochemical properties of Ni82.3Cr7Fe3Si4.5B3.2 glassy alloy in different acid proticity has been investigated utilizing AC and DC methods. Firstly, the handling of experimental data on the temperature dependence of charge transfer resistance, as well as corrosion current density permits us to determine the values of classical Arrhenius parameters as well as the thermodynamic ones considered approximately independent of temperature. This leads us to deduce a global interpretation on the phenomenon of corrosion and polarization. Secondly, the deviation to the linearity of the Arrhenius behavior and the real dependence on temperature of the thermodynamic parameters, permit us to clearly quantify the effect of the acid proticity and define, for the first time, the concept of current Arrhenius parameters and the current thermodynamic ones, as well as the modeling of the enthalpy–enthalpy compensation. Moreover, the effect of temperature can be investigated using the Vogel–Fulcher–Tammann model to reveal that the corresponding Vogel temperature has an interesting physical meaning.

The Influence of Boron and Carbon Addition on the Glass Formation and Mechanical Properties of High Entropy (Fe, Co, Ni, Cr, Mo)-(B, C) Glassy Alloys

Coatings made from metallic glasses are a promising solution for protecting surfaces of materials in various challenging environments. From an engineering perspective, glassy alloy coatings containing carbon are of greater importance compared to those without carbon but containing boron. Despite anticipating improved coating characteristics, there is no data on using high entropy glassy alloy as a coating material. In this paper, we investigated the influence of the simultaneous addition of boron and carbon elements on the glass-forming ability, thermal stability, crystallization behavior, yield strength, hardness, and corrosion resistance of high entropy (Fe, Co, Ni, Cr, Mo)-(B, C) glassy alloys. It was found that the content of boron and carbon had a significant effect on the improvements of glass-forming ability, mechanical properties, and corrosion resistance. The (Fe0.25Co0.25Ni0.25Cr0.125Mo0.125)75(B0.7C0.3)25 bulk glassy alloy exhibits high glass-forming ability, high yield strength of 3500 MPa, Vickers hardness of 1240, and the highest corrosion resistance among the alloys. We also discussed the reason for their good engineering properties, and the possibility of using high entropy glassy alloys as coating materials, in addition to the guidelines for designing high-performance multicomponent glassy alloys.

Assessment of the classical theory validity through Cu50Zr50 nucleation and growth molecular dynamics simulations

One of the most promising candidates for novel glass-forming alloy design is atomic-scale simulations, primarily due to their capability to compute properties that are usually experimentally difficult to measure. This work aims to use classical molecular dynamics (MD) simulations to obtain the key nucleation and growth variables for the glass-forming Cu50Zr50 alloy while verifying the validity of the Classical Nucleation Theory (CNT). Through CNT equations and simulation data, nucleation and growth rates could be determined, revealing good agreement between CNT expressions and simulation results. The data were compared with other simulation and experimental data, providing reasonable evidence that supports the validity of CNT for describing the solidification behavior of glassy alloys. Simulation data seems to overestimate the experimental growth rate by one order of magnitude, a trend that requires further investigation and correlation with the system/potential to enhance the method’s robustness and reliability for other alloy compositions.

Sb induced effect on glass transition, crystallization kinetics and optical properties of Se96Sn4 alloy

Se96-xSn4Sbx (x = 0, 2, 4, 6, and 8) glassy alloys were prepared using the melt quench technique. Thermal measurements were carried out using differential scanning calorimetry (DSC) in non-isothermal mode. Kissinger and Moynihan methods are used for glass transition kinetics, while Kissinger, Takhor, and Augis-Bennet methods are used to study crystallization kinetics. The inclusion of Sb in the alloy increased the glass transition temperature (Tg), activation energy of the glass transition (Et), and activation energy of crystallisation (Ec). The chemical bond approach has been used to explain the results. The rising trend of Ec is explained by the production of SnSe4/2 structural units with energies greater than those of Se–Se and Se–Sb bonds, increasing the degree of cross-linking. The dimensionality of crystal growth changes from one to two with the addition of Sb to the Se-Sn alloy. The criterion for thermal stability was addressed by using the enthalpy emitted during the crystallization process. In addition, Kubelka-Munk transformation and Tauc plots were used to calculate the band gaps. The energy gap (Eg) decreases from 3.72 to 1.60 eV as the Sb concentration increases from 0 to 8 atm%.