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The tribological behaviors of Cu-based bulk metallic glass (BMG) Cu50.2Zr40.8Ti8.5Nb0.5 and conventional nickel–aluminum bronze (NAB) reference material were investigated in air and in 3.5% NaCl solution, respectively. The tribology tests were performed at room temperature using a reciprocating tribometer at a sliding speed of 1 m min−1 against a 6-mm diameter ZrO2 ball. When sliding in air, the friction coefficient of Cu-based BMG decreases with the applied loads (5 N, 10N, and 20 N), and the wear behavior is mainly affected by abrasion, delamination, and oxidation. In particular, the wear-rate of Cu-based BMG is about 22 times lower than that of conventional NAB when sliding in the air under a load of 5 N. When sliding in 3.5 wt% NaCl solution, Cu-based BMG demonstrates better static-corrosion resistance but worse tribocorrosion resistance compared with conventional NAB. Due to the combined effects of corrosion and lubrication caused by the solution, the wear-rate of the BMG in NaCl solution increases at 5 N, but decreases at 20 N when compared with the corresponding wear in air. The tribocorrosion of Cu-based BMG is mainly controlled by abrasive wear and the synergistic effects of abrasion and corrosion. By applying −1.3 V cathodic potential, the corrosive wear-rate of Cu-based BMG at 5 N was reduced by nearly 50%. This work provides an experimental reference for the tribological evaluation of Cu-based BMG in different environments.

This paper reports the creep behavior of a nickel-based single crystal alloy and the creep fracture mechanism under high temperature and low stress was discussed. The creep curves were analyzed with the Kelvin model. The retardation spectra suggest that the involved atoms during creep need more relaxation time to achieve the viscous flow, nevertheless, the creep under the stress of 120 MPa may be caused by the mismatch of dislocation motion and visco-plastic deformation. The fracture morphologies of crept alloys indicate that the nickel base single crystal alloy presents micro-pore aggregation fracture mechanism under the condition of high temperature and low stress creep.

BACKGROUND: This study aimed to evaluate the clinical performance of low serum calcium and phosphorus in discriminative diagnosis of the severity of patients with coronavirus disease 2019 (COVID-19). We conducted a single-center hospital-based study and consecutively recruited 122 suspected and 104 confirmed patients with COVID-19 during January 24 to April 25, 2020. Clinical risk factors of COVID-19 were identified. The discriminative power of low calcium and phosphorus regarding the disease severity was evaluated. Low calcium and low phosphorus are more prevalent in severe or critical COVID-19 patients than moderate COVID-19 patients (odds ratio [OR], 15.07; 95% confidence interval [CI], 1.59-143.18 for calcium; OR, 6.90; 95% CI, 2.43-19.64 for phosphorus). The specificity in detecting the severe or critical patients among COVID-19 patients reached 98.5% (95% CI, 92.0%-99.7%) and 84.8% (95% CI, 74.3%-91.6%) by low calcium and low phosphorus, respectively, albeit with suboptimal sensitivity. Calcium and phosphorus combined with lymphocyte count could obtain the best discriminative performance for the severe COVID-19 patients (area under the curve [AUC] = 0.80), and combined with oxygenation index was promising (AUC = 0.71). Similar discriminative performances of low calcium and low phosphorus were found between suspected and confirmed COVID-19 patient. Low calcium and low phosphorus could indicate the severity of COVID-19 patients, and may be utilized as promising clinical biomarkers for discriminative diagnosis.

This paper reported the alloying effects in the non-isothermal crystallization of as-cast bulk metallic glasses. Three kinds of Al, Ni and Si elements with minor quantity of 0.5 at% were individually added into a base Cu55Zr37Ti8 bulk metallic glass. Differential scanning calorimetry was utilized to characterize the crystalline processes during heating, and Johnson–Mehl–Avrami equation was adopted to determine and evaluate the crystallization kinetic parameters. The results disclose that alloying processing with 0.5 at% of Al, Ni and Si elements altered the crystallization kinetic behaviors. Alloying with 0.5 at% of Ni performs more remarkable constraint on the nucleation and growth of the crystallization with regard to alloying with the same quantity of Al and Si elements in the base bulk metallic glass and favors the suppression of crystallization.

The effects of Sr addition on the microstructure and mechanical properties of in-situ ZrB2 nanoparticles reinforced AlSi9Cu3 composites synthesized via direct melt reaction were systematically investigated. The addition of Sr could modify the morphology of eutectic silicon particles and refine the second dendrite arm spacing of α-Al dendrites. Alternatively, the ZrB2 nanoparticles were also refined and distributed more homogenously, and nanoparticle agglomerations were reduced with the addition of Sr element. The results demonstrated that the addition of 0.06 wt% of Sr element can reach the optimal refinement of the second dendrite arm spacing of α-Al and the modification of eutectic Si. In this case, the ultimate tensile strength, yield strength and elongation reached 330 MPa, 226 MPa and 15.70%, respectively, which were remarkably enhancement in comparison with the base alloy. Keywords: Aluminum matrix composites, In-situ nanoparticles, Sr modification, Refinement, Particles distribution

We propose and demonstrate for the first time an approach to synthesize nanostructured photocatalysts through combustion of metal alloys in amorphous state. This approach takes advantage of metastable state and composition homogeneity of amorphous alloys and produce photocatalysts with uniformly dispersed oxides at nanoscale by self-propagating reactions. Using CuZr amorphous ribbons as an example, we demonstrate a photocatalyst containing copper oxides and ZrO2 in the form of 10 nm-thick nanosheet with 2 nm nanopores. The new catalyst substantially outperforms those previously reported copper oxide catalysts in experiments of photocatalytic degradation of methylene blue and direct methanol fuel cells. This study opens up an avenue to fabricate nanostructured functional oxides in an environment friendly approach not only for photocatalyst but also for oxide based nanoelectronic and nanoionic applications.

In this work, an as-cast Fe50Ni30P13C7 bulk metallic glass, which has large plastic strain (>20%) and without final fracture in compression, was systematically investigated with nanoindentation creep to uncover the structural relationships with its plastic deformation. The X-ray diffraction, differential scanning calorimetry and transmission electronic microscopy indicated that as-cast bulk metallic glass is of fully and stably amorphous nature. Three positions, from inner to outer of as-cast bulk metallic glass, were used to experimentally disclose the gradient structure in indication with gradually changes in creep compliance and retardation spectra. In a same creep holding time, the creep displacement continuously and gradually decreases from outer to inner of as-cast specimen and the creep compliance and retardation spectrum of each position indicate the outer position is more relaxed and relaxed state trends in a same subsequence with creep displacement. The work suggests that the structural gradient of as-cast Fe50Ni30P13C7 bulk metallic glass is responsible for large plasticity.

This work investigates the correlation of electronic structure and β relaxation of La70Ni15Al15, La70Co15Al15 and La70Cu15Al15 bulk metallic glasses. X-ray photoelectron spectroscopy measurements discovered that the activity of electrons around Fermi level of La70Ni15Al15 and La70Co15Al15 glasses with peak-like strong β relaxation are more intense than La70Cu15Al15 glass with shoulder-like weak β relaxation and correspondingly the core levels of electronic states of Ni and Co elements are seriously split whereas that of Cu is not. This work might provide a different route to understand the origin of β relaxation rather than the normal thinking of atomic packing structure.

The influence of Sr on two- and three-dimensional morphology of primary Si in Zn–27Al–3Si alloy was investigated. Distribution and crystalline structure of Sr were analyzed by using synchrotron radiation micro-beam. The results show that Sr could modify polygonal primary Si to nearly standard spherical shape. Modified primary Si enriched with Sr, which partially evolves as Al2Si2Sr, while partially presents as independent atoms. Sr promotes high-density paralleled and intersected {111}Si twins during the growth of primary Si. These observations thus provide experiment evidence to support the modification mechanisms based on impurity-induced twinning and poisoning of twin plane reentrant edge.

Microstructure evolution and phase transformation of metallic glasses (MGs) could occur under heating condition or mechanical deformation. The cross-section of as-cast Zr55Cu30Ni5Al10 MG rod was impacted by the solid particles when subjected to erosion in slurry flow. The surface microstructure was observed by XRD before and after slurry erosion. And the stress-driven de-vitrification increases with the increase of erosion time. A microstructure evolution layer with 1–2 μm thickness was formed on the topmost eroded surface. And a short range atomic ordering prevails in the microstructure evolution layer with crystalline size around 2–3 nm embedded in the amorphous matrix. The XPS analysis reveals that most of the metal elements in the MG surface, except for Cu, were oxidized. And a composite layer with ZrO2 and Al2O3 phases were formed in the topmost surface after slurry erosion. The cooling rate during solidification of MG has a strong influence on the slurry erosion induced nanocrystallization. And a lower cooling rate favors the surface nanocrystallization because of lower activation energy and thermo-stability. Finally, the slurry erosion induced surface nanocrystallization and microstructure evolution result in surface hardening and strengthening. Moreover, the microstructure evolution mechanisms were discussed and it is related to the cooling rate of solidification and the impact-induced temperature rise, as well as the combined effects of the impact-induced plastic flow, inter-diffusion and oxidation of the metal elements.

In this paper, the influence of nanoparticle fraction on Portevin-Le Chatelier effect of ZrB2 nanoparticle reinforced AA6xxx composites was investigated and friction stir processing was used to uniformize the distribution of nanoparticles. The results indicated that the population of serrations decreases with increasing the fraction of ZrB2 particles, with stress-drop serrations dominate the early stages of deformation while the stress-up serrations increase with the strain. The stress distribution complies with bimodal configuration, and 2 peaks become closing with the increasing fraction of nanoparticles. The interval for unconstrained motion of dislocation is responsible for the suppression of Portevin-Le Chatelier effect. The mean interval decreases with increasing the nanoparticles fraction. The inter-twisted dislocations in small intervals continuously dedicate to instant balance of stress-drop serrations, strengthen composites and favor the plastic deformation.

This work reports the room-temperature nanoindentation creep behaviors of as-cast and aged CuZrTiNb bulk metallic glasses and investigates the ageing influences on the heterogeneity evolution. With ageing, the hardness shows an increasing trend with the ageing time and indicates 3 stepped increase. The aged specimens still have amorphous nature. The ageing shows a strong effect on the ending creep displacement but a weak effect on the initial displacement. Meanwhile, it decreases the resistance to localized plastic deformation but increases the creep resistance of current bulk metallic glass. The analysis of compliance and retardation spectra demonstrates that the quantity of large hole decreases but that of small void increases with ageing.

Efficient, stable electrocatalysts are required to promote the hydrogen evolution reaction (HER) to obtain hydrogen as a clean, sustainable fuel via water splitting. In the present work, ribbons of the metallic glass Fe40Co40P13C7 were produced using a conventional melt-spinning technique and assessed as electrocatalysts for HER. In 0.5 M H2SO4, these ribbons generated an overpotential of 118 mV at a current density of 10 mA cm−2. This overpotential remained essentially constant over 20 h under these conditions. Based on the excellent properties, these glassy ribbons represent a new type of highly active, robust HER catalyst suitable for practical applications.

In this paper, we prepared the binary Cu-Ti nanoglass films by composite deposition technique. The X-ray diffraction and atomic force microscopy indicate that as-synthesized films are consisted of nanoglass with apparent interfaces. The room temperature creep behavior and strain rate sensitivity of as-synthesized nanoglass films were investigated with nanoindetation and explored that Cu58Ti42 has a better creep-resistance property at room temperature but Cu42Ti58 has a more relaxed structure. The as-synthesized nanoglass films exhibit anomalously negative strain rate sensitivity.

A series of Fe-based bulk metallic glasses were fabricated by a conventional copper mold casting method using a kind of Fe-B industrial raw alloy. It is found that Fe-B-Y-Nb bulk metallic glass with 3 at% of Co addition possesses the best glass forming ability, thermal stability, hardness, magnetic property and anti-corrosion property. The hardness test result indicates a synchronically trend with glass-forming ability parameters. The excellent glass-forming ability and a combination of good mechanical and functional properties suggest that the alloys in this work might be good candidates for commercial use.

The experimental results concerning the effects of Mo on the glass-forming ability (GFA), thermal stability, and mechanical, anticorrosion, and magnetic properties of an (Fe71.2B24Y4.8)96Nb4 bulk metallic glass (BMG) were presented. An industrial Fe–B alloy was used as the raw material, and a series of Fe-based BMGs were synthesized. In BMGs with the Mo contents of approximately 1at%–2at%, the cast alloy reached a critical diameter of 6 mm. The hardness and fracture strength also reached their maximum values in this alloy system. However, the anticorrosion and magnetic properties of the BMGs were not substantially improved by the addition of Mo. The low cost, good GFA, high hardness, and high fracture strength of the Fe-based BMGs developed in this work suggest that they are potential candidates for commercial applications.

This work studied the effect of the size of specimens on the β relaxation. Taking La70Ni15Al15 bulk metallic glass as a model material, via dynamic mechanical analysis, we found that the thickness of specimens can affect the intensity of β relaxation. Specifically, increasing the thickness of specimens can enhance intensity of β relaxation. For this enhancement, we proposed that the involvedly total free volume facilitates the β relaxed process. This finding gives a new insight on the structural relaxation of bulk metallic glasses, especially for understanding of origin of β relaxation.

The effects of W addition on the corrosion behaviors of FeCoNiCrMn high entropy alloy composites in 3.5 wt.%NaCl solution are investigated in this study. The X-ray diffraction and scanning electron microscopy suggest that the quantity of added W particles results in the increasing quantity of particles in the composites and large amount of cohesionless phases covering the matrix occur in the alloy with 1.0 molar ratio of W element. The trend of corrosion potential current density means that all W-added high entropy alloy composites have a better corrosion resistance referring to the base high entropy alloy composites and 0.8 molar ratio of W element into base generates a best corrosion resistance in the current work. The Electrochemical impedance spectra and compositional analysis of corroded surface of as-cast high entropy alloys demonstrate that W particles act as anode in the composites and Fe-Mn-Cr is as the cathode.

Besides the extreme complexity of gear dynamics, the fault diagnosis results in terms of vibration signal are sometimes easily misled and even distorted by the interference of transmission channel or other components like bearings, bars. Recently, the research field of Instantaneous Angular Speed (IAS) has attracted significant attentions due to its own advantages over conventional vibration analysis. On the basis of IAS signal's advantages, this paper presents a new feature extraction method by combining the Empirical Mode Decomposition (EMD) and Autocorrelation Local Cepstrum (ALC) for fault diagnosis of sophisticated multistage gearbox. Firstly, as a pre-processing step, signal reconstruction is employed to address the oversampled issue caused by the high resolution of the angular sensor and the test speed. Then the adaptive EMD is used to acquire a number of Intrinsic Mode Functions (IMFs). Nevertheless, not all the IMFs are needed for the further analysis since different IMFs have different sensitivities to fault. Hence, the cosine similarity metric is introduced to select the most sensitive IMF. Even though, the sensitive IMF is still insufficient for the gear fault diagnosis due to the weakness of the fault component related to the gear fault. Therefore, as the final step, ALC is used for the purpose of signal de-noising and feature extraction. The effectiveness and robustness of the new approach has been validated experimentally on the basis of two gear test rigs with gears under different working conditions. Diagnosis results show that the new approach is capable of effectively handling the gear fault diagnosis i.e., the highlighted quefrency and its rahmonics corresponding to the rotary period and its multiple are displayed clearly in the cepstrum record of the proposed method.

We report the observation that UV irradiation substantially improves pitting corrosion resistance of Cu-based bulk metallic glasses. Specifically, two Cu-based bulk metallic glasses in this study showed more stable passive films under UV irradiation than under irradiation-free condition when polarized in 3.5 wt.% NaCl aqueous solution. This finding indicates that Cu-based bulk metallic glasses are promising to serve in high UV irradiation and corrosive environments.

In this paper, the roles of agglomerations of ZrB2 nanoparticles in the in-situ ZrB2-nanoparticle-reinforced AA6061 composites were investigated via the analyses of strain hardening and serrated flow behaviors during the deformation. The tensile testing demonstrates that the composite with 2 vol% of nanoparticles has a yield strength of 74.1 MPa, ultimate strength of 181.1 MPa and plastic strain of 20.2%, respectively, which are better than the composites with 1 vol% and 3 vol% of nanoparticles. The increasing values of strain-hardening coefficients suggest that the mobility of dislocations was decreased. The strain hardening rate indicates that the as-cast 2 vol% ZrB2-nanoparticles-reinforced composite has the best strain hardening ability but the composite with 3 vol% ZrB2 nanoparticles has the lowest one which is attributed to the strain concentration in the agglomerations initiating the crack through the cohesive region between ZrB2 nanoparticles. The serration analysis reveals that the population of serrations with ≤0.5 MPa of stress drop is a key feature for stabilizing plastic deformation.

In this paper, the dramatical increase in the apparent activation energy (defined as potential-upsurge) of tensile creep of a high entropy Al20Ce20La20Ni20Y20 metallic glass was discovered. The temperature referring to the occurrence of potential upsurge is around the onset relaxation temperature of as-spun specimen (110 °C (383 K)) measured by differential scanning calorimetry. Below 110 °C, the value of apparent activation energy is determined to be 3.9 kJ/mol, nevertheless, this value dramatically increases to 35.4 kJ/mol above 110 °C. Kelvin model was utilized to resolve the creep mechanism. The short-time relaxation behavior indicates a dramatical increase above 110 °C. The work reveals that the extension and retardation of smaller defects are responsible for the potential-upsurge in the apparent activation energy of tensile creep.

In the current work, the tensile creep behaviors of a (Cu0.5Zr0.5)92Ta8 metallic glass composite were investigated. The precipitates and the metallic glass matrix in the as-spun ribbons have nearly same compositions. The addition of Ta element enhances the thermal stability of binary Cu50Zr50 metallic glass. The apparent activation energies of tensile creep increase with the applied stress, and the values of strain rate sensitivity decrease from 0.39 to 0.16 with the increasing applied temperatures. The correlationship of activation energy and activation volume suggests that the largest activation energy corresponds to the smallest activation volume, and vice versa. The values of strain rate sensitivity are noticeably smaller than reported values, which is related to the softening of (Cu0.5Zr0.5)92Ta8 ribbons with the increasing creep temperatures.

In this paper, glass-forming ability, viscosity, fragility and microhardness of three Cu-based bulk metallic glasses are evaluated by differential scanning calorimetry, thermomechanical analysis and hardness testing. The results suggest that Y element can effectively affect the packing state and properties of Cu-based bulk metallic glasses. The variation of glass-forming ability, viscosity, fragility index and hardness indicates that alloying with low quantity of additions can remarkably change the characteristic temperatures during glass transition stage but cannot cause an apparent modification in the solidification/melting stage.

The discovery of the silicon carbonate through chemical reaction between porous SiO2 and gaseous CO2 addressed a long-standing question regarding whether the reaction between CO2 and SiO2 is possible. However, the detailed atomic structure of silicon carbonate and associated reaction mechanism are still largely unknown. We explore structure changes of silicon carbonate with pressure and temperature based on systematic ab initio molecular dynamics simulations. Our simulations suggest that the reaction proceeds at the surface of the porous SiO2. Increasing number of CO2 molecules can take part in the reaction by increasing either the pressure or temperature. The final product of the reaction exhibits amorphous structures, where most C atoms and Si atoms are 3-fold and 6-fold coordinated, respectively. The fraction of differently coordinated C (Si) atoms is pressure dependent, and as a result, the structure of the final product is pressure dependent as well. When releasing the pressure, part of the reaction product decomposes into CO2 molecules and SiO2 tetrahedrons. However more than 50% of C atoms are still in 3-fold coordination, implying that stable silicon carbonate may be obtained via repeated annealing under high pressure. The mechanism underlying this chemical reaction is predicted with two possible reaction pathways identified. Moreover, the reaction transition curve is obtained from the extensive simulation, which can be useful to guide the synthesis of silicon carbonate from the reaction between SiO2 and CO2.

To improve the poor plasticity of bulk metallic glasses, this work reports the microalloying of a bulk metallic glass to tailor the microstructures and to enhance its plasticity. The selection of alloying elements, Hf and Mo which are soluble in Ti, is determined by binary phase diagrams. The X-ray diffraction and microstructural analysis demonstrate that the microstructural evolution of as-cast alloys is accompanied with the addition of alloying elements. The glass-forming ability of as-cast alloys increases with the addition of Hf and Mo elements, respectively. The yield strength and plasticity of both as-cast alloys are affected with the quantity of alloying elements. In addition, the intrinsic nature of alloying elements and the interaction among the alloying elements and base compositions affect the hardness of as-cast alloys. Summarily, addition of soluble alloying elements in a component of base composition can enhance the plasticity of bulk metallic glasses. Keywords: Bulk metallic glasses, Composites, Microstructures, Plasticity

Fe-based metallic glass (amorphous Fe–Si–B ribbons) was successfully fabricated and shown to be an efficient catalyst of the photo-decomposition of rhodamine B (RhB). The effects of various factors on the photodecomposition were investigated. The catalyst dosage and the wavelength and intensity of the light source were all found to strongly influence the reaction rate. A nearly complete degradation of RhB (20 mg L−1) was achieved within 15 min by 50 mg L−1 Fe–Si–B catalyst and 1 mM oxalic acid when illuminated with 125 W UV light. The Fe–Si–B catalyst was also found to exhibit good structural stability and no loss of performance for three cycles. Based on the results of these experiments, we conclude that the amorphous Fe–Si–B ribbons and oxalic acid constitute a promising heterogeneous Fenton-like system for industrial wastewater treatment.

A general evaluation criterion for the coverage performance of LEO constellations that can be used for various constellation configurations is proposed. The method transforms the minimum elevation angle characteristics at the specified latitude limits into the standard number of satellites with the same coverage performance, and the ratio with respect to the actual number of satellites in a constellation is defined as the index of coverage performance. Because this index is actually the average coverage level of each satellite, it is suitable for different configurations. Therefore, the optimal configuration can be selected for global coverage or coverage of specific latitudes. Using the evaluation method, the coverage index for three typical Walker- δ constellations was computed; these indexes were: Globalstar, 0.51; Celestri, 0.46; and NeLS, 0.45. Using the general evaluation method, the optimum Walker- δ constellation suitable for China is determined. The final optimum configuration was selected as 46°:42/7/0, or an inclination angle of 46°, a total of 42 satellites in 7 orbital planes, and a phasing factor of 0. The coverage performance index is as high as 0.566, providing coverage with elevation angles greater than 13° in the targeted area at an orbital altitude of 1400 km. This configuration can continuously cover China with a minimum elevation of 20°, and the coverage range includes the latitudes from 24.5° to 53°, which is definitely suitable for China.

This paper reports the microstructure evolution of Cu50.2 Zr40.8Ti9−xNbx (x = 0.5, 1.0, and 2.0 at.%) bulk metallic glass and bulk metallic glass composites accompanied with the addition of Nb and the corresponding mechanical properties. The X-ray diffraction and characterization of microstructures demonstrate that the microstructures of as-cast alloys undergo a composite-amorphous evolution. DSC analysis indicates that the glass-forming ability of as-cast alloys increases with addition of Nb. The microstructure evolution can be contributed to the combination of the stabilization of Nb on precipitated crystalline phases and cooling time. 1.0 at.% Nb-alloyed sample has the best plasticity (15.1%) and the highest fracture strength (2205 MPa) among three as-cast alloys. This work suggests that the uniformly dispersed tiny crystalline phases in glassy matrix can enhance the plasticity of bulk metallic glasses.

In the present work, the role of Cu addition on the tensile properties of both as-cast and solution-treated Al–11Si–0.3Mg alloys was systematically investigated. For as-cast alloy, a fine and uniform microstructure can be obtained by employing efficient refinement and modification with the combinative addition of B, La and Sr. The addition of Cu causes slight coarsening of α-Al dendrite, but has insignificant effect on the size and morphology of eutectic Si particles, resulting in a promotion of strength coupled with unremarkable reduction of elongation. The strengthening effects of Cu addition mainly depends on the weight ratio of Cu/Mg in the experimental alloy, of which the quality value of Q calculated shows that the optimized tensile properties of Cu-dropped Al–11Si–0.3Mg can be achieved with the weight ratio of Cu/Mg of 5:1, referring to 383 MPa and 430 MPa in as-cast condition and solution-treated condition, respectively.

The effects of La addition on the microstructure and tensile properties of B-refined and Sr-modified Al-11Si-1.5Cu-0.3Mg casting alloys were investigated. With a trace addition of La (0.05wt%–0.1wt%), the mutual poisoning effect between B and Sr can be neutralized by the formation of LaB6 rather than SrB6. By employing a La/B weight ratio of 2:1, uniform microstructures, which are characterized by well refined α-Al grains and adequately modified eutectic Si particles as well as the incorporation of precipitated strengthening intermetallics, are obtained and lead to appreciable tensile properties with an ultimate tensile strength of 270 MPa and elongation of 5.8%.

An efficient heterogeneous catalyst, Fe-based metallic glass (Fe–Si–B amorphous ribbon), was successfully prepared for Fenton-like degradation of rhodamine B (RhB) by a melt-spinning method. The catalyst was characterized using XRD and SEM. The effects of various reaction parameters such as H2O2 dosage, temperature, initial pH value, Fe–Si–B dosage and initial RhB concentration on the degradation of RhB were studied. Almost complete degradation of RhB (20 mg L−1) was achieved within only 10 min by 0.5 g L−1 Fe–Si–B catalyst and 1.6 mM H2O2 at pH 3.0 at 295 K. Kinetic analyses showed that the degradation process could be described by a pseudo-first-order kinetic model. The catalytic stability was also investigated and it was found that the Fe–Si–B catalyst exhibited good structural stability and no loss of performance even after three cycles. It was concluded that the Fe–Si–B amorphous ribbon was a potential heterogeneous Fenton-like catalyst for industrial wastewater treatment.

In this paper, with the combinative addition of La and B elements, the grain refinement of Al–Si alloys with different contents of Si was achieved. Compared to individual addition of B element, the combinative addition of La and B elements can effectively refine the grains of Al–Si alloys. The addition of La element suppresses the mutual poisoning between Sr and B elements, benefiting the formation of a fully modified eutectic silicon structure in the Al–Si alloys. This work also indicates that the tensile properties, especially the elongation, of Al–Si alloys are enhanced with the addition of La element.

In this paper, a computational thermodynamic approach was used to design the compositions of bulk metallic glass composites. This approach indicates that both the liquidus temperature and the solidification temperature range of the primary phase of a Cu–Zr–Ti–Si alloy system increase with the addition of silicon. With the aid of the calculation, the crystal-embedded Cu-based bulk metallic glass composites have been fabricated successfully. The as-cast composites were characterized by X-ray diffraction and energy dispersive spectroscopy. The characterizations demonstrate that the increase of in the liquidus temperature and the extension of the primary phase region facilitate the formation of primary phase-embedded composite structures. This work suggests that the computational thermodynamics approach can be serve as a potential tool to construct bulk metallic glass composites, especially to fabricate the primary phases-embedded bulk metallic glass composites. The findings of this work can be utilized to understand the formation of composite structures of bulk metallic glass composites.

In this paper, a new equation was rationally generalized from the reduced glass transition temperature. This equation indicates that solidification range can be used for describing glass-forming ability, which can be calculated with the aid of computational thermodynamic approach. Based on this scenario, several new Cu-based bulk metallic glasses in the ternary Cu–Zr–Ti alloy system were discovered. The as-cast samples were characterized by X-ray diffraction and transmission electronic microscopy. The results indicate that as-cast samples have monolithic amorphous nature. Thermal analysis validates that the smaller solidification range is closely related to the higher glass-forming ability, which is contributed to the effect of solidification time on the formation of bulk metallic glasses. This work also suggests that solidus can influence glass formation.

In this paper, newly designed plastic Cu 51 Zr 37 Ti 8 Ni 4 bulk metallic glass has been successfully fabricated. By purposely increasing the liquidus temperature in a quaternary Cu–Zr–Ti–Ni alloy system, glass-forming ability of as-cast bulk metallic glasses shows a desired decrease trend. As-cast Cu 51 Zr 37 Ti 8 Ni 4 , which has a lower glass-forming ability and a higher liquidus temperature than Cu 52 Zr 37 Ti 8 Ni 3 , is of monolithic amorphous structure, and also displays remarkable plasticity of 10.5% together with the fracture strength of 2145 MPa. Multiple and interactive shear bands can be discovered on the fracture surface of fractured Cu 51 Zr 37 Ti 8 Ni 4 . In addition, the deformation of Cu 51 Zr 37 Ti 8 Ni 4 shows serrated flow behavior. By a statistics analysis of serrations in the stress–time curve, the serrated flow behavior of the sample follows the self-organized critical behavior. This work suggests that, with the aid of CALPHAD, composition design of plastic bulk metallic glasses can be achieved according to the liquidus perspective.

A monolithic Cu-based bulk metallic glass (BMG), having plastic strain of more than 26% together with fracture strength of 2471 MPa, was fabricated by copper mold casting. This plastic strain has never seen in monolithic Cu-based BMGs containing more than 50 at.% Cu. The excellent plasticity is attributed to a large amount of free volume induced by minor addition of nickel, resulting in multiple shear bands formation, branching and interaction.