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The intrinsic origins and formation of atomic-scale structure in multicomponent alloys remain largely unknown owing to limited simulations and inaccessible experiments. Herein, we report the formation of three-dimensional periodicity from a disordered atomic-scale structure to an imperfect/perfect ordered cluster and finally to long-range translational and rotational symmetry coupled with Nb heterogeneity. Significant atomic-scale structural clustering and atomic arrangements involving solvent or solute atoms simultaneously occurred during isothermal annealing. A close relationship between atomic-scale structural evolution and composition variation has important implications in depicting the chemical and topological packing during the early crystallization stage in metallic glasses. This work can provide a comprehensive understanding of how short-range orders evolve into long-range periodicity and will further shed light on the origins and nature of metallic glasses.

The functional copper nanocomposites (Cu NCs) have received increasing attention in the environmental catalysis application for wastewater treatment due to their superior catalytic activity and reactivity. However, overcoming the pH limitations towards the neutral and alkaline wastewater remains a tricky challenge. In this work, we demonstrate a green strategy to synthesize Cu NCs with coexistence of active Cu, Cu2O and ZrO2 by self-propagating combustion of metallic glassy ribbons, which exhibit the extremely superior catalytic performance for degradation reaction, providing full conversion of organic dyes completely to the environmental friendly small species (efficiency > 99%) under acidic, neutral and alkaline conditions. Compared with all other catalysts developed thus far, the novel Cu NCs catalysts with more active sites present much enhanced catalytic capability of degradation efficiency without the use of any chemical reagents for neutral and alkaline organic dye solutions. The possible decomposition pathways of organic dyes for different pH systems were systematically investigated. More importantly, the two kinds of catalytic mechanism related to high reactivity of nanoscale Cu/Cu2O and strong oxidizing capability of activated •OH /•O2− radicals can also be successfully confirmed under different pH conditions. The green synthetic approach can be extended to design the various M-based nanocomposites (M = Fe, Co, Ni, Ag, Pd) as efficient catalysts for the functional applications of many chemical reactions.

The development of heterogeneous catalysts of non-noble metal with both high reactivity and activity for the oxygen reduction reaction in catalytic degradation of organic pollutants is a formidable challenge. Here we design an innovative and rational self-propagating combustion method for metallic glasses to synthesize Cu-based composite with high catalytic activity, in which the main compounds of Cu and Cu2O are uniformly dispersed on the surface. The Cu/Cu2O/ZrO2 composite exhibits superior catalytic capability compared to other catalysts. The degradation efficiencies all are approximately 99.8% and the total organic carbon (TOC) removals can be up to more than 60% under optimal reaction conditions. The degradation intermediates and possible decomposition pathways of two dyes for Fenton-like catalytic system were systematically investigated. Importantly, the possible catalytic mechanisms can be proposed catalytic oxidation reaction by activated hydroxyl radicals (·OH) and superoxide anion radicals (·O2−). These findings provide a new strategy to design efficient composite catalysts for the functional application of wastewater treatment.

The compression behavior of a Ti-23.1Nb-2.0Zr-1.0O (at.%) alloy was investigated at strain rates from 0.1 s−1 to 1000 s−1 and temperatures from 100 °C to 200 °C on a Gleeble 3800 system and Split Hopkinson Pressure Bar (SHPB) compressive tester. Optical microscopy, electron backscatter diffraction (EBSD), X-ray diffraction (XRD) and transmission electron microscopy (TEM) were employed to characterize the microstructure evolution during the deformation. Numerous deformation phenomena, including dislocation slip, twinning of both {332}〈113〉 and {112}〈111〉 modes, stress-induced α” martensite (SIMα”) and stress-induced ω (SIω) transformations, were observed. The preferred activation of twinning and SIω transformations was observed in the sample compressed at lower temperatures and/or higher strain rates. The underlying mechanism is that twinning and stress induced phase transformations are attribute to higher stress concentrations at β grain boundaries and additional energy supplied by a higher strain rate, as well as high stacking fault energy because of higher temperature.

Sustainably regenerated, environmentally friendly, natural loofah sponge is promising to become a multi-functional bio-carbon material, especially in the field of electromagnetic shielding, due to its unique hierarchical structure. In this work, highly efficient electromagnetic shielding composites were obtained based on CVD carbon-coated carbonized loofah sponge (CCLS) and directionally arrayed MXene aerogels through a simple and pollution-free freeze-drying method. The three-dimensional skeleton of CCLS was able to provide a mechanically strong support for the MXene aerogel and endow the composites with a good foundation network for electric conduction and shielding electromagnetic waves. When the CVD carbon coating time was 60 hours, the compressive strength and modulus of CCLS reached 0.979 MPa and 10.881 MPa, respectively, and an electrical conductivity of 28.34 S m−1 was attained. In particular, the directionally arrayed MXene aerogel with a microporous structure filled the macropore vacancies in the CCLS skeleton, giving the composite prominent anisotropy. The maximum conductivity and average total electromagnetic shielding effectiveness of the composites prepared achieved levels of 55.99 S m−1 and 70.0 dB, respectively. Importantly, the composite showed excellent flame resistance and thermal stability. The electromagnetic shielding effectiveness value of the composites could still reach 42.6 dB after being burnt in an alcohol flame for 120 s. This research could further widen the practical application and development of natural biological materials and aerogels in various fields such as aerospace, medical equipment, electronic devices, and energy management.

Crystalline-amorphous composite have the potential to achieve high strength and high ductility through manipulation of their microstructures. Here, we fabricate a TiZr-based alloy with micrometer-size equiaxed grains that are made up of three-dimensional bicontinuous crystalline-amorphous nanoarchitectures (3D-BCANs). In situ tension and compression tests reveal that the BCANs exhibit enhanced ductility and strain hardening capability compared to both amorphous and crystalline phases, which impart ultra-high yield strength (~1.80 GPa), ultimate tensile strength (~2.3 GPa), and large uniform ductility (~7.0%) into the TiZr-based alloy. Experiments combined with finite element simulations reveal the synergetic deformation mechanisms; i.e., the amorphous phase imposes extra strain hardening to crystalline domains while crystalline domains prevent the premature shear localization in the amorphous phases. These mechanisms endow our material with an effective strength–ductility–strain hardening combination.

正应力如何影响金属玻璃高温下的变形方式转变目前仍不清楚. 本文通过同时构建金属玻璃在压缩和拉伸下的变形图, 发现存在显著的正应力效应, 即拉伸正应力能极大地促进剪切局域化到均匀变形的转变, 而压缩正应力则可能轻微抑制该转变. 本研究结果强调了应力状态在金属玻璃高温变形中的关键作用, 并预示着可通过调整局部应力状态来更好地控制金属玻璃的热塑性成形.

To overcome the trade-off between the devisable microstructure and the excellent tensile ductility of bulk metallic glass composites (BMGCs), a novel ex-situ and in-situ hybrid strategy is successfully proposed to design a series of the work-hardenable ductile Ti-based multilayered BMGCs (ML-BMGCs). The as-prepared ML-BMGCs, consisting of α-phases, β-phases and amorphous phases, exhibit a controllable multilayered structure of the Ti layers and the amorphous layers with alternative distribution. The size and volume fraction of the crystalline phases are tuned by Nb microalloying. It is found that the ML-BMGCs possess a suitable size and volume fraction of the crystalline phases when Nb microalloying content are 5% (at.) or 8% (at.), and they obtain an optimum combination of the specific strength of 243 MPa g kg­1 or 216 MPa g kg−1, and tensile plasticity of 4.33%±0.1% or 5.10%±0.1%. The deformation mechanism of the as-prepared ML-BMGCs during tension is also revealed. The ex-situ Ti layers and in-situ dendrites together effectively serve as absorbers to suppress the propagation of shear bands and multiply shear bands. And the deformation of ex-situ α-Ti phases by dislocation slip and the transformation from in-situ metastable β-Ti phase to orthorhombic α"-Ti during tension impart significant work-hardening capability to the ML-BMGCs. The present study provides a guidance of developing novel high-performance BMGCs with a controllable microstructure.

Metallic glasses with the unique disordered atomic structure and metastable nature have been recently applied to degrade the azo dyes and other organic pollutants based on their superior catalytic performance. In this work, the functional properties of six CuZr-based metallic glassy ribbons with the different nominal components in degrading Acid Orange Ⅱ (AO Ⅱ) azo dyes were investigated. The Cu47.5Zr46Al6.5 metallic glassy ribbons could exhibit the more advanced catalytic performance for degradation process, which could completely degrade azo dye aqueous solution within 30 min. Additionally, the Cu47.5Zr46Al6.5 metallic glassy ribbons also showed the excellent cyclic stability along with approximately 97.68 % degradation efficiency after 10 cycles. These excellent catalytic performance and stability are closely related to the synergistic effect of exposed copper nanoparticles and produced copper oxides in the reaction, which contributes to accelerate the generation of more hydroxyl radicals (·OH) to react with dye molecules. Our findings can be able to develop a novel potential metallic glassy material for the functional application of wastewater treatment.

So far, some investigations related to the corrosion mechanism of Zr-based metallic glasses in solutions containing Cl− have been developed. However, few attentions have been paid to the situation in F−-containing solution. This paper describes the corrosion behaviours of Zr52Al10Ni6Cu32 bulk metallic glass (BMG) in NaF and NaCl aqueous solutions. The corrosion mechanism of Zr-based BMG in F--containing solution was proposed for the first time. It was found that in NaCl solutions, Zr-based BMG samples underwent typical pitting corrosion. Selective dissolution of Zr, Al and enrichment of Cu were observed in corrosion pits. However, corrosion occurred in the form of general breakdown of passive film in NaF solutions. Such difference is interpreted in terms of the binding ability of anions to surrounding molecules, i.e., Cl− with loose surrounding water passes through the passive film to cause pitting; F− with a tight surrounding molecules layer absorbs on passive film then coordinates with cations from matrix.

The mechanical behaviors of Zr43.5Cu43.5Ni4Al8Nb1, Zr55.4Cu31.6Ni4Al8Nb1, Ti32.8Zr30.2Ni5.3Cu9Be22.7 (at.%) metallic glass at different strain rates were studied. For all the present alloys, the dispersion over 700 MPa was observed on the strength in the repeated dynamic compressions, which was much stronger than that of the quasi-static compressive strength. Such the dispersion of the dynamic compressive strength was well correlated with the corresponding fracture behaviors. The area of fracture surface was calculated and also showed a strong dispersion for all the fractured specimens tested at the strain rate of 500 s−1 and 1000 s−1. All the specimens showed a linear relationship between the square of dynamic compressive strength and the area of fracture surface in the dynamic compression tests. This phenomenon was mainly thought to be related to the difference of mean initial free volume concentration of different samples, stress concentration caused by the split Hopkinson pressure bar experimental setup and high sensitivity of defects under dynamic deformation. These findings were beneficial to deeply understand the effect of strain rate on the mechanical properties of the metallic glass.

The energy state and atomic level structure of metallic glasses (MGs) are very sensitive to their cooling rates, and a lower cooling rate generally causes a lower energy and more relaxed state of MGs. In this work, the Zr41.2Ti13.8Cu12.5Ni10Be22.5 (Vit. 1) ribbons with a thickness of 40 μm and 110 μm and the strips with a thickness of 320 μm and 490 μm were produced by single-roll melt spinning and twin-roll casting, respectively. The increase in thickness of either ribbons or strips results in a lower energy state with a smaller relaxation enthalpy, a lower content of free volume, and a higher hardness. Although the cooling rate of the twin-roll produced 320 μm-thick strip is almost one magnitude lower than that of the single-roll produced 110 μm-thick ribbon, the former, however, possesses a rejuvenated energy state as compared to the latter. Molecular dynamics simulations reveal that the squeezing force during twin-roll casting affects the evolution of connection types of clusters, and the 2-atom and 4-atom connections are prone to be retained, which results in a higher energy state of MGs. Such a rejuvenation process during twin-roll casting can overwhelm the relaxation process caused by the lower cooling rate. Therefore, twin-roll casting is not only a method being capable for producing strips with a large thickness, but also prone to obtain a high energy state of the MG strip.

Metallic glasses (MGs) with superior catalytic performance have attracted great attention in wastewater treatment. However, the low durability of the extensively studied Fe-based MGs impedes their degradation efficiencies and practical applications. In this study, Cu46Zr44.5Al7.5Gd2 MGs are prepared to degrade organic water contaminants for the first time, and they exhibit excellent catalytic activity and high sustainability. The degradation reactions maintain a high degradation efficiency of more than 95% within 10 min when the Cu-based MG ribbons are reused 80 times. The degradation reaction occurs more easily with the Cu-based MGs compared with other MGs due to the lower thermal activation energy barrier of 17 kJ mol−1. Cu nanocrystals precipitating in the Cu-based MGs are the catalytically active species of the degradation reaction, resulting in the high degradation efficiency and sustainability of the Cu-based MGs. Our study will promote the widespread application of MGs as functional materials.

Metallic glasses (MGs) with the unique long-range disordered and short-range ordered atomic structure have attracted extensive attention in the field of environmental catalysis due to their advanced catalytic capability. Herein, CuZr-based MGs are first proven to exhibit superior catalytic performance toward the degradation of organic pollutants compared to the annealed ribbons with different crystal structures; many Cu nanocomposites are gradually in situ precipitated on the surface of the ribbons. The enhanced catalytic behavior is mainly attributed to the random atomic packing structure accelerating electron transport and providing sufficient active sites. On the other hand, the active species, for example, ·OH, ·O

In order to adapt to the launch velocity of modern artillery, it is necessary to study the fracture mechanism of the high-velocity penetration of penetrators. Therefore, the penetration fracture mode of tungsten-fiber-reinforced Zr-based bulk metallic glass matrix composite (WF/Zr-MG) rods at a high velocity is studied. An experiment on WF/Zr-MG rods penetrating into rolled homogeneous armor steel (RHA) was carried out at 1470~1650 m/s. The experimental results show that the higher penetration ability of WF/Zr-MG rods not only results from their “self-sharpening” feature, but also due to the fact they have a longer quasi-steady penetration phase than tungsten alloy (WHA) rods. Above 1500 m/s, the penetration fracture mode of the WF/Zr-MG rod is the bending and backflow of tungsten fibers. Our theoretical calculation shows that the deformation mode of the Zr-based bulk metallic glass matrix (Zr-MG) is an important factor affecting the penetration fracture mode of the WF/Zr-MG rod. When the impact velocity increases from 1000 m/s to 1500 m/s, the deformation mode of Zr-MG changes from shear localization to non-Newtonian flow, leading to a change in the penetration fracture mode of the WF/Zr-MG rod from shear fracture to the bending and backflow of tungsten fibers.

Metallic glasses (MGs) with a unique atomic structure have been widely used in the catalytic degradation of organic pollutants in the recent years. Fe78Si9B13 MGs exhibited excellent catalytic performance for the degradation of oily wastewater in a Fenton-like system for the first time. The oil removal and chemical oxygen demand (COD) removal from the oily wastewater were 72.67% and 70.18% within 60 min, respectively. Quenching experiments were performed to verify the production of active hydroxyl radicals (·OH) by activating hydrogen peroxide (H2O2). The formation of ·OH species can significantly contribute to the degradation reaction of oily wastewater. Fe78Si9B13 MG ribbons were highly efficient materials that exhibited superior reactivity towards H2O2 activation in oily wastewater treatment. The study revealed the catalytic capability of metallic glasses, presenting extensive prospects of their applications in oily wastewater treatment.

Discovering new catalytic applications of Fe-based metallic glasses (MGs) besides the decolorization of azo dyes is an active topic. In this article, two types of coke wastewater before anaerobic treatment (I) and after aerobic treatment (II) are applied to investigate the catalytic performance of Fe78Si8B14 and Fe73.5Nb3Cu1Si13.5B9 MGs in Fenton-like system. The experimental parameters, including hydrogen peroxide concentration, temperature and solution pH are detailed studied. The Fe78Si8B14 MGs exhibit a superior catalytic capability in wastewater treatment compared with the Fe73.5Nb3Cu1Si13.5B9 MGs. The Fe73.5Nb3Cu1Si13.5B9 MGs provide less reactive sites and lower Fe content in the coke wastewater due to the inclusion of Nb, restricting the generation of hydroxyl radicals and hindering the degradation reaction. The chemical oxygen demand removal efficiency of the wastewater I and II treated with Fe78Si8B14 MGs could achieve 71% within 30 min and 89% within 60 min under the optimal condition, respectively. These results expand the practical applications of Fe-based MGs in treating environmental pollutants.