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The ability to widely tune the optical properties of amorphous alloys is highly desirable especially for their potential applications in optoelectronic devices. In this work, we demonstrate that introducing oxygen into an amorphous alloy system of Co-Fe-Ta-B enables the formation of various amorphous derivatives ranging from metals to semiconductors, and eventually to insulators. These oxygen-containing amorphous derivatives gradually become transparent with the opened bandgaps, leading to a continuous increase in their optical transmittance. Furthermore, the reflective metal-type amorphous alloy and transparent insulator-type amorphous oxide of the system can be integrated together to realize the full-color tuning over the entire visible spectral range. This provides a new way to develop large-area color coatings with high design flexibility and full-color tun-ability. We envisage that the design concept proposed in this work is also applicable to many other amorphous alloy systems, from which all types of amorphous materials including alloys, semiconductors and insulators may be developed to show unprecedented optical functionalities.

The characteristics of in-depth hardness distribution in the high-temperature carburized case of Nb-microalloyed gear steel before and after cryogenic treatment were studied by nano-indentation method and Vickers hardness method. The results showed that there was no significant difference in Vickers hardness of the carburized case before and after cryogenic treatment, while the nano-hardness of the carburized case was increased after cryogenic treatment. The change of nano-hardness could be related to the decrease in retained austenite content. The retained austenite content in the surface of the carburized case was 26%, which was reduced to 18% after cryogenic treatment at − 196 °C, with the nano-hardness increased from 11.8 to 12.6 GPa. Nano-indentation can be used to reliably measure the properties of the high-temperature carburized case with fine retained austenite for Nb-microalloyed gear steel.

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

High entropy alloys exhibit a composition design route that different from conventional alloys. However, whether the high configurational entropy is the key factor that stabilizes the room temperature single phase solid solution is still under debate. Here we use a perturbation model to evaluate their phase stabilities. According to the calculation results of 7085 alloys, it clearly indicates that a stable single phase is rare when constituent elements increase. The effect of increased entropy cannot balance the fast-increased driving force for the formation of intermetallics. Although it is not favored by thermodynamics, the frequently observed room temperature single-phase solid solutions can still form due to dynamic effect, which from the other side, provides a method to tune the microstructure and therefore the mechanical properties.

Here we propose a model to understand the influence of structural inhomogeneity on the shear band behaviours of metallic glasses. By considering the inhomogeneous structure and stress concentration...

Herein, a novel method is proposed to synthesize B-ZnO NWA by simply immersing the Zn NWA in NaOH solution at room temperature (25 °C). Based on the systematic investigation of various factors that affect the growth of B-ZnO NWA, the growth mechanism of B-ZnO NWA is clarified. Guided by the growth mechanism, the control of the morphology of B-ZnO NWA is achieved by adjusting the pore structure of anodized aluminum oxide templates, hot-pressing parameters, NaOH concentration, solution temperature, and immersion time. In contrast to previous reports, the prepared B-ZnO NWA has hollow trunks, which can further increase the specific area of B-ZnO NWA. Considering the facile, environmental, and low-cost synthesis, the prepared B-ZnO NWA with tunable morphology has great prospects in a wide range of applications, especially those related to the conversion and utilization of solar energy, which are gaining increasing interest nowadays.

In this paper, we report that two newly designed high entropy bulk metallic glasses (HE-BMGs), Ti20Hf20Cu20Ni20Be20 with a critical diameter of 2 mm, and Ti16.7Zr16.7Nb16.7Cu16.7Ni16.7Be16.7 with a critical diameter of 1.5 mm, can be fabricated by copper mold casting method. These newly developed HE-BMGs exhibited a high fracture strength over 2300 MPa. The glass forming ability and atomic size distribution characteristics of the HE-BMGs are discussed in detail. Moreover, a parameter δ′ was proposed to evaluate the atomic size distribution characteristics in different HEAs. It showed that this new parameter is closely related to the degree of lattice distortion and phase selection of high-entropy alloys. Adjusting the value of δ′ parameter by similar element substitution/addition would be beneficial for designing high entropy bulk metallic glasses.

Metallic glasses (MGs) have attracted great attention in wastewater treatment because of their high reactivity arising from amorphous structure, large residual stress and high density of low coordination sites. However, the reactivity of MGs would gradually slow down with time due to the passivation of active sites by corrosion products, resulting in limited long-term reactivity, which is also an unsolved key issue for established crystalline zero valent iron (ZVI) technology. Here, such problems are successfully overcome by introducing nanoscale chemical inhomogeneities in Fe-based MG (Fe-MGI), which apparently contributes to local galvanic cell effect and accelerates electron transfer during degradation process. More importantly, the selective depletion of Fe0 causes local volume shrinkage and crack formation, leading to self-peeling of precipitated corrosion products and reacted regions. Thereby fresh low coordination sites could be continuously provided, counteracting the mass transport and reactivity deteriorating problem. Consequently, Fe-MGI demonstrates excellent long-term reactivity and self-refreshing properties even in neutral solution. The present results provide not only a new candidate but also a new route of designing ZVI materials for wastewater treatment.

Since increasing Ti content in Ti-based metallic glasses would benefit their specific strength, developing Ti-based bulk metallic glasses (BMGs) with high Ti content has drawn great attention of researchers. However, excessive Ti content usually deteriorates their glass forming ability (GFA), especially for Ti-based BMGs with Ti content higher than 50 at.%. Here, based on the Ti55Zr15Be20Ni10 BMG with a critical diameter of 5 mm, the (Ti55Zr15Be20Ni10)100-xFex alloys were designed and investigated. The (Ti55Zr15Be20Ni10)96Fe4 BMG exhibited a critical diameter of 10 mm, suggesting GFA of the Ti55Zr15Be20Ni10 BMG could be improved by Fe addition. In addition, their yield strength increased with Fe addition, thus the specific strength was enhanced from 3.98 × 105 N m/kg to 4.46 × 105 N m/kg, providing the most optimal scheme of specific strength and GFA among the reported Ti-based BMGs. The developed BMGs exhibited high pitting potentials in 3.5 wt.% NaCl aqueous solution, which were 1.8~2.8 times higher than that of 304 stainless steel. The present result shows that the developed Ti-based BMGs containing high Ti content, combined with high specific strength, large glass forming ability and good corrosion resistance, are promising for applications requring lightweight alloys.

Oxygen reduction reaction (ORR) plays a major role in the efficient operation of many important electrochemical energy devices. Herein, a novel catalyst of nanoporous silver (NPS) is in-situ synthesized by a high voltage anodization method in 0.1 M KOH which also serves as the electrolyte for the catalysis of ORR. Favored by the continuous pore channels, the mass transfer is enhanced within the NPS. Theoretical calculations suggest that the strengthened interactions between OOH intermediates and the dominant Ag(110) surfaces on NPS as revealed by an adsorption test reduce the activation energy for the rate determining step and thus accelerate the ORR. Due to the enhanced mass transfer and facile kinetics, the NPS exhibits excellent ORR activity and even outperforms the commercial Pt/C. Fascinating more, the service life of NPS is significantly extended through an in-situ regeneration process. The integration concept we demonstrate in this work shed new lights on the preparation of long-life functional materials with high performance in applications including but not limited to ORR.

In this paper, a laser metal deposition (LMD) process has been applied to the fabrications of CrMnFeCoNi high entropy alloys. The microstructures and mechanical properties of the CrMnFeCoNi alloys prepared using casting technique and LMD technique have been investigated. It has been found that the CrMnFeCoNi samples prepared using casting show a coarse dendritic structure. The microstructures of LMD samples contain both columnar grains and/or equiaxed grains, and the proportion of columnar grains and equiaxed grains can be adjusted by changing the laser power. Besides, the mechanical properties of LMD samples can be adjusted by changing laser power, due to columnar to equiaxed transitions (CET) that are effected by solidification mode and the heat flux direction of LMD process. It is worth to mention that the mechanical properties of the 1400 W samples produced using LMD are better than those produced by casting, which is rarely observed. Furthermore, CrMnFeCoNi alloys prepared using LMD show excellent mechanical properties at cryogenic temperatures.

We investigated the effects of the austenitizing temperature on the microstructure, hardness, and tensile properties of case-carburized steel after vacuum carburization at 930 °C and then re-austenitization at 820–900 °C followed by oil quenching and tempering. The results show that fractures occurred early with the increase in the austenitizing temperature, although all the carburized specimens showed a similar case hardness of 800 HV0.2 and case depth of 1.2 mm. The highest fracture stress of 1919 MPa was obtained for the experimental steel when the austenitizing temperature was 840 °C due to its fine microstructure and relatively high percentage of retained austenite transformed into martensite during the tensile tests. We also found that the stress–strain behavior of case-carburized specimens could be described by the area-weighted curves of the carburized case and the core in combination. The strain hardening exponent was about 0.4 and did not vary with the increase in the austenitizing temperature. We concluded that the optimum austenitizing temperature was around 840 °C for the experimental steel.

In this work, a new multi-component (CrFeMoNbZr)Ox system was developed. The thin films presented dual-phase amorphous structures, comprising a dominant amorphous alloy phase and a small amount of an amorphous oxide phase. The thin films showed higher hardness and better corrosion resistance than a commercial Zr-based alloy. The combined properties of high hardness and superior corrosion-resistance make the amorphous thin film a candidate for coating materials on commercial Zr-based alloys for engineering applications.

Metallic glasses (MGs) are promising candidates for catalysts with high efficiency for dyeing wastewater remediation, due to their metastable nature, disordered structure, and large residual stresses. However, dyeing wastewater usually contains a high concentration of inorganic ions which may have adverse effects on the degradation process, while the impacts of these ions on MGs' degradation capability have often been overlooked and still remain unknown. Thus, the roles of inorganic ions (Cl-, NO3-, SO42-, and H2PO4-) on the degradation of azo dye by Fe-based MG with nominal composition of Fe81Si4B14Cu1 were systematically investigated. The results showed that the inorganic ions have significant influence on MG's surface morphology, degradation capability, mineralization and durability. All these aspects need to be considered prior to application of MGs for azo dyes degradation in real natural contaminated water or saline wastewater.

Hybrid soft magnetic composites are fabricated using bimodal amorphous Fe73Si11B11C3Cr2 and crystalline Fe50Co50 powders via MIM. When Fe73Si11B11C3Cr2 powder is partially substituted by Fe50Co50 powder which forms a bimodal distribution, permeability decreases with, but the saturation induction increases with increasing fraction of Fe50Co50. Composites with high fraction of Fe50Co50 have good magnetic saturation and improved bias performances. Core loss is more influenced by particle size distribution. Finer Fe50Co50 powders are distributed in interstices and lead to a more loosely packed structure. On one hand, loosely packed structure increasing the interspacing of magnetic powders gives rise to low eddy current loss. On the other hand, loosely packed structure increases flowability of powders and results in low-viscosity feedstock, which can be molded with low injection pressure resulting in small internal stresses, giving rise to low core loss. As a result, hybrid SMCs with 50% fraction of Fe50Co50 powder exhibits the best comprehensive magnetic properties.

低温电输运特性是非晶态材料理论研究中的关键问题. 通过在Ti-Zr-Hf-Cu-Ni高熵非晶合金薄膜材料中掺入氧, 可以诱导其在低温下显示出异常的电输运行为. 低于8 K时, 掺氧高熵非晶合金薄膜的电阻率分别与温度和外加磁场强度的1/2次方（即 T 1/2和 H 1/2）呈线性关系. 研究表明, 氧的掺入增强了高熵非晶合金薄膜中电子-电子间的库伦作用和电子自旋之间的交互作用, 从而导致含氧高熵非晶合金薄膜的低温异常磁电输运行为. 因此，我们可通过对高熵非晶合金材料掺氧实现对该材料低温导电性能的调控.

The poor thermoplastic formability greatly restrains the wide application of Ti-based bulk metallic glasses. In this study, the thermoplastic formability of Ti-Zr-Be BMG has been dramatically improved by alloying method. The representative Ti41Zr25Be28Fe6 alloy exhibits a wide supercooled liquid region of ∼123 K and low viscosity of ∼106 Pa s in its supercooled liquid region, resulting in the best thermoplastic formability among all the developed Ti-based BMGs. Nanorods arrays can be successfully fabricated even in air with the help of a wetting layer. Moreover, the good glass-forming ability and excellent mechanical properties also make it applicable as engineering materials.

Three-dimensional flowerlike nanostructured metal oxides attached on the surfaces of Fe-based multi-phase nanocrystalline ribbons (Fe-MNRs) were prepared by a simple way (through immersing the Fe-MNRs in Orange II solution). It has been found that the as-prepared Fe-MNRs with 3D flowerlike nanostructures (Fe-MNRs + FNs) exhibit good absorption property for a typical heavy metal ion (CrVI) in wastewater, while Fe-MNRs do not possess such properties. The Fe-MNRs + FNs could remove 99% CrVI ions from the solution in 40 min, and this adsorption property can be attributed to the ion exchange between CrVI and surface hydroxyl groups (O–H) of 3D flowerlike nanostructures. The present result suggests that the Fe-MNRs + FNs, prepared by facile way, possess great potentials in removing heavy metallic ions in wastewater.

An efficient and selective catalyst is in urgent need for carbon dioxide electroreduction and silver is one of the promising candidates with affordable costs. Here we fabricated large-scale vertically standing Ag nanowire arrays with high crystallinity and electrical conductivity as carbon dioxide electroreduction catalysts by a simple nanomolding method that was usually considered not feasible for metallic crystalline materials. A great enhancement of current densities and selectivity for CO at moderate potentials was achieved. The current density for CO ( jco) of Ag nanowire array with 200 nm in diameter was more than 2500 times larger than that of Ag foil at an overpotential of 0.49 V with an efficiency over 90%. The origin of enhanced performances are attributed to greatly increased electrochemically active surface area (ECSA) and higher intrinsic activity compared to those of polycrystalline Ag foil. More low-coordinated sites on the nanowires which can stabilize the CO2 intermediate better are responsible for the high intrinsic activity. In addition, the impact of surface morphology that induces limited mass transportation on reaction selectivity and efficiency of nanowire arrays with different diameters was also discussed.

Nanoindentation tests on the Ti20Zr20Hf20Be20(Cu20-xNix) (x = 0, 12.5, 20 at.%) high entropy bulk metallic glasses (HE-BMGs) indicate both their average hardness and moduli show a significant loading strain rate-dependent behaviour. In special, the strain rate sensitivity of hardness measured for the prepared TiZrHfBeNi HE-BMG is up to 0.056 which is the highest value reported for BMGs so far. Such high strain rate sensitivity of hardness is likely due to the high-entropy effect, which makes the amorphous structure more homogeneous. In addition, the high entropy coupled with amorphous structure manifests as small shear transformation zone (STZ) volumes that could make the shear bands hard to be initiated.

We report the formation of a ferromagnetic Co55.0Fe24.5Ta0.1B20.4 amorphous alloy by magnetron sputtering, which exhibits positive magnetoresistance without saturation even in very high magnetic fields. This suggests that the s-like electrons responsible for the electrical conduction are spin-polarized through s-d hybridization. Owing to the electromagnetic interplay of the spin-polarized conduction electrons with the local magnetic moments, the electric-field control of room-temperature ferromagnetism is realized in the amorphous alloy. Our results offer insights for exploring the multi-functionalities of ferromagnetic amorphous alloys and extending their applications to a wide variety of electronics including magnetic tunnel junctions and compact disks. Keywords: Ferromagnetic amorphous alloys, Magnetic properties, Magnetoresistance, Voltage control of magnetism

Molecular dynamics simulations were employed to investigate the effect of void defect on the shear band nucleation in a Cu64Zr36 metallic glass. Unlike uniform samples, the samples with void defects can form shear bands at a much lower strain. Finite element simulation revealed stress concentration near the voids, which can explain the early formation of shear bands. The shear band behaviors are also influenced by the size, shape and distribution of the defects. These findings can provide simulation support to understand the shear band heterogeneous nucleation process of metallic glasses in the real case.

A series of Fe75.5-xNixCu1Nb3Si12.5B8 (x=0.5-10 at. %) soft magnetic dual-phase alloys with low permeability were synthesized by adjusting Ni content. Effect of annealing on the soft-magnetic properties, crystallization behavior and microstructure were investigated. It is found that the temperature interval between the two crystallization temperature is significantly decreased from 169 to 127°C when the Ni content of the alloys increases from x=0.5 to x=10, which greatly reduces the optimum annealing temperature range. The alloys with higher Ni content are prone to exhibit lower permeability, and the alloys with the composition of Fe65.5Ni10Cu1Nb3Si12.5B8 exhibit excellent soft-magnetic properties, including the low permeability of 3350, low coercivity of about 1.26 A/m and low remanence of 8 mT. The combination of low permeability and excellent soft-magnetic properties makes the FeNiCuNbSiB nanocrystalline alloys to be a kind of promising material for common mode chokes and current transformer with direct current tolerance.

Graphene has shown many attractive properties while the difficulties in the fabrication of high-quality graphene have been a significant bottleneck in its applications. Here we report the discovery of high-quality graphene obtained from the solidified equiatomic CrFeCoNiC high-entropy alloy. Graphite flakes can be peeled off from the surface of the as-cast CrFeCoNiC high-entropy alloy, and single or multilayer graphene can be further exfoliated. The mechanical properties of the graphene are investigated by an atomic force microscope, and the result confirms the discovery of high-quality graphene. The transmission electron microscopy and Raman spectroscopy are applied to further characterize the quality of the graphene and show that the graphene has high-quality with few defects, comparable to the graphene obtained from highly oriented pyrolytic graphite. The thermodynamic calculation is applied to investigate the solidification process of the high-entropy alloy and reveals the mechanism of the formation of graphite on the surface.

In this work, we prepared equiatomic AlCoCrFeNi high-entropy alloy (HEA)-particle-toughened, Zr-based metallic glass composites by spark plasma sintering. By adding HEA particles as the second phase, the strength and plasticity of the Zr-based metallic glass composites improved concomitantly. After fracture, high-density dislocations and nanocrystals were formed in the HEA particles due to local severe plastic deformation, which consumed massive strain energy to enable the resistance to crack formation. Substantial lattice distortion imparted a remarkable work-hardening capacity to the HEAs and enhanced crack-tip dislocation trapping, and thus led to an extreme refinement of the grain size. Finite-element analyses indicated that the strain hardening behavior of HEA particles reduced the magnitude of strain localization, promoted generation of multiple shear bands, and stabilized shear band propagation. We attribute the enhanced strength-ductility synergy in the current composites to high-density dislocations and nanocrystal formation in the HEA particles, and stable propagation of multiple shear bands.