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High entropy alloys (HEAs) have presented potential applications in nuclear power plants owing to their novel atomic structure based high irradiation resistance. However, understanding of He-ion irradiation of HEAs is still lacking. In this work, we reveal He-ion irradiation resistance of HEA CrMnFeCoNi by comparison study with a pure Ni and a 304 stainless steel (304SS). It is found that the damage structure in the three materials can be characterized with He bubbles and stacking faults/stacking fault tetrahedrons ((SFs/SFTs), which show a similar depth distribution after He-ion irradiation at both RT and 450 °C. Although the He bubbles have a similar size about 2 nm after irradiation at RT, the He bubble sizes of the HEA, 304SS, and Ni increase to 4.0 ± 0.9, 5.3 ± 1.0 and 6.7 ± 1.0 nm after irradiation at 450 °C, respectively. Moreover, the density of SFs/SFTs displays in an order of Ni

Excessive consumption of electrical energy has hampered the widespread application of electrochemical technology for degradation of various contaminants. In this paper, a Fe-based metallic glass (MG) was demonstrated as a new type of electrocatalyst to effectively and economically degrade an azo dye. In comparison to other typical electrodes, Fe-based MG electrodes exhibit a minimized degradation time, and the specific energy is 4–6 orders of magnitude lower than that of dimensionally stable anode (DSA), metal-like boron-doped diamond (BDD) and other electrodes. As sacrificial electrode materials, Fe-based MGs have less specific electrode mass consumption than iron electrodes. The use of Fe-based MGs will promote the practical application of electrochemical technology and the use of MGs as functional materials.

New Ti-based bulk metallic glasses (BMGs) of Ti32.8+XZr30.2−XNi5.3Cu9Be22.7 (3 ≤ |X| ≤ 15, at.%) with large size were prepared. The results reveal that the forming of primary icosahedral quasicrystal phase (I-phase) and the enthalpy of the primary crystallization (ΔH1) were closely related to the glass forming abilities (GFAs). The crystallization product of the metallic glass alloys at primary crystallization state is a metastable I-phase. It is demonstrated that apparent activation energy for crystallization obtained by fitting the Kissinger equation at Tx temperature increases with the increase of Ti concentration, while GFAs deteriorate. The ΔH1 of metallic glasses declines with the increase of Ti concentration. The Ti32.8+XZr30.2−XNi5.3Cu9Be22.7 possess high similar compressive fracture strength of about 1800 MPa, which is one of the best options as structural materials on account of high specific strength and low cost.

A new Ti-based BMGC with excellent tensile plasticity and significant work-hardening capacity was successfully developed. The microstructure, mechanical behaviors and toughening mechanisms were investigated in details by SEM, XRD, TEM and Nano-indentation. It is found that the stress-induced martensitic transformation from β to α″ phase and the mechanical twinning in the α″ phase combined to account for these mechanical behaviors. The current work offers a new perspective for developing in situ dendrite reinforced BMGCs with improved homogeneous ductility and significant work-hardening capacity.

Flexible magnetoelectric (ME) nanocomposites with a strong coupling between ferromagnetism and ferroelectricity are of significant importance from the point of view of next-generation flexible electronic devices. However, a high loading of magnetic nanomaterials is needed to achieve preferable ME response due to the size mismatch of the magnetostrictive phase and piezoelectric phase. In this work, ultra-small CoFe2O4 nanoparticles were prepared to match the size of the polar crystal in poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), and 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS) is introduced to enhance the interplay between P(VDF-TrFE) and CoFe2O4. The above multiple effects promote a good connection between the magnetostrictive phase and the piezoelectric phase. Therefore, an effective transference of stress from CoFe2O4 to P(VDF-TrFE) can be achieved. The as-prepared P(VDF-TrFE)/CoFe2O4@POTS exhibits a high ME coupling coefficient of 34 mV cm-1 Oe-1 when the content of CoFe2O4@POTS is 20 wt%. The low loading of fillers ensures the flexibility of ME nanocomposite films.

The high-entropy metallic glasses (HEMGs), combining the characteristics of high-entropy alloys (HEAs) and metallic glasses (MGs), have recently appeared and become the research focus, due to their good glass-forming ability and high strength. However, the application of HEMGs as structural material is restricted owing to the limited tensile plasticity and absence of dislocation-dominated deformation mechanism. To resolve this pressing issue, a stable β-phase HEMG composite (β-type HEMGC) Ti20Zr20Hf20Nb16Co5Be19 composed of the bcc refractory HEA (RHEA) dendrites and the HEMG matrix was fabricated. Ti20Zr20Hf20Nb16Co5Be19 not only exhibits good tensile ductility, but also has the improved work-hardening capability under room temperature tension. Essentially, the dislocation-dominated deformation mechanism plays a significant role in achieving the excellent combination of good tensile plasticity and improved work-hardening capability of the stable β-type HEMGC. The tensile ductility of Ti20Zr20Hf20Nb16Co5Be19 is attributed to the dislocation-slip mechanism induced by high-stable HEA dendrites, and the dislocation pile-up phenomenon has a great influence on the improved work-hardening capability of composite. The present results provide an indepth understanding of the deformation behavior of stable β-type HEMGCs, and a reference for how to improve the strength-ductility combination of HEMG-matrix composites.

Fe-based metallic glasses (MGs) not only are an industrially produced amorphous zero-valent iron (AZVI) with a promising reductive degradability to azo dyes but also can activate persulfate (PS) with sulfate radicals (SO4•-, Eo = 2.5–3.1V) for wastewater remediation. In this study, acid orange II (AOII) was rapidly and efficiently decolored by Fe78Si8B14 MG/PS system with a 99% degradation rate in 8 min. Based on monitoring the degradation rate and the concentration of Fe2+/Fe3+, a two-step degradation mechanism is proposed, that one is deductive degradation by AZVI with products of small organic molecules and Fe2+, and the other is oxidative degradation, where AZVI and Fe2+ activate PS with products of SO4•- and •OH confirmed by the electron spin resonance (ESR) analysis test. The orthogonal experimental design proves that the effects of the experiment operating parameters on the decolorization efficiency from high to low are Fe-based MGs dosage, PS dosage, and reaction temperature. Meanwhile, the high efficiency of the Fe-based MGs/PS system is also illustrated for the mineralization of AOII by an indication of the TOC removal rate as high as 57%. This work gives new insight into Fe-based MGs for activating PS and will accelerate the application of Fe-based MGs as catalysts in the field of wastewater treatment.

The stability of body-centered cubic (β) phases and phase transformations of NbxHfZrTi (x = 1, 0.6, 0.4 and 0.2) high-entropy alloys (HEAs) were investigated. Three types of transformations were observed: the β → ω transformation during cooling in Nb0.2 HEA, the deformation-induced β → α″ and β → α′ transformations in Nb0.4 and Nb0.2 HEAs, respectively. This implies that the phonon anomalies, T11/2(110) and L2/3(111), as the origins of phase transformations in simple Ti, Zr and Hf alloys, also exist in composition-complex TiZrHf-based HEAs. However, the very small fraction of deformation-induced α′/α″ martensite in fractured Nb0.4 and Nb0.2 suggests a sluggish effect of transformation as compared with simple β-Ti alloys.

Up to now, few work has concerned about the composition design strategy in the field of in-situ dendrite bulk metallic glass composites (BMGCs) for the difficulty to mediate single element in the multi-component system. In this work, an innovative composition design strategy was proposed, and a novel series of in-situ β dendrite reinforced Ti-based BMGCs were prepared. It was found that the real composition of the in-situ formed dendrites and amorphous phase is well consistent with the designed one. Accordingly, the dendrite composition is tailored monotonically and precisely, while the composition and volume fraction keep similar for the amorphous matrix in the composites. The microstructure of the dendrites and the mechanical properties and mechanisms of the overall composites are essentially controlled by the dendrite composition. According to the corresponding deformation mechanisms which transform from stress-induced martensitic transformation and mechanical twinning to dislocation slip, these alloys can be classified into two groups: the stress-induced martensitic transformation type and the none-phase transformation type. The composition design strategy proposed in this work and the correlation between the dendrite composition and the mechanical mechanisms may provide useful guidance for the development of in-situ β dendrite reinforced BMGCs with optimized mechanical properties.

A Ta wire-reinforced Zr-based bulk metallic glass composite with a new type of structure was prepared successfully by the method of liquid metal infiltration. Ta wires distribute uniformly in the metallic glass matrix in the form of spirals. The composite exhibits two yield stages under compressive stress, and the samples are compressed into thin pancakes. The micro-cracks originate at the interface between the Ta wire and the metallic glass matrix and propagate perpendicularly to the interface, which then induce multiple shear bands in the metallic glass matrix due to the stress concentration. Shear cracks form in the metallic glass matrix during the continued loading process as a result of the interaction of shear bands. Deformation bands of Ta wires occur under the impact of shear bands. The local stress fields in the composite are changed obviously due to the introduction of the spiral-formed reinforcements. The investigation of the deformation behavior and mechanism suggests a new method for the application of bulk metallic glass composites as the structural materials.

The effects of Ti element on the corrosion resistance of the metallic glass Zr51.3Al10Ni6Cu31.8Ag0.1Y0.8 in aqueous solution with various chloride concentrations were investigated, and the effect mechanism was discussed. X-ray diffraction confirmed that Ti-added Zr51.3Al10Ni6Cu31.8Ag0.1Y0.8 metallic glasses with diameter of 3 mm were all metallic glasses. Weight loss and electrochemical method were introduced to characterize their corrosion resistance, and X-ray photoelectron spectroscopy study was used to characterize the passive film composition. The results show that the corrosion resistance of metallic glass is significantly improved with Ti addition, and Zr dioxides dominate in passive film during corrosion when Ti content is low. High Ti addition can lead to an obvious accumulation of Ti dioxides, which results in a thicker, Ti-enriched protective passive film.

A novel strategy to design bulk metallic glass composite is proposed. The foils with the composition of the β phase in the in-situ TiZr-based composite are prepared. The in-situ composite matrix and the β foils are composited at the semi-solid temperature using the modified melt infiltration method. The mechanical properties of the newly prepared laminar composite reinforced with both ex- and in-situ β phases are improved remarkably. The composite shows controllable structure based on the phase equilibrium, and the corresponding mechanism is discussed thermodynamically. The interaction kinetics is studied by the modified liquid-bridge experiments and a dissolution kinetics model is deduced. The laminar composite shows obvious plasticity and work hardening behavior because of the introduction of multiscale ductile β phase. The multiple shear bands in the metallic glass and the β phase, and the phase transformation of β to α" contribute to the high performance of the composite. This study provides a new design approach to manipulate the microstructure and further improve the mechanical properties of the composites.

New ferromagnetic high-entropy bulk metallic glasses (HE-BMGs) with superior glass-forming ability (GFA) and high strength were developed in the pseudo quaternary FeCoNi(P, C, B, Si) system. The HE-BMG rods were fabricated by copper mold casting method in the composition range of Fe25Co25Ni25(P0.3–0.5C0.1–0.3B0.2–0.3Si0.1–0.3)25, in which the Fe25Co25Ni25(P0.4C0.2B0.2Si0.2)25 and Fe25Co25Ni25(P0.5C0.1B0.2Si0.2)25 alloys possess the largest critical diameter of 2.0 mm. The HE-BMGs exhibit excellent soft magnetic and mechanical properties, i.e., low coercivity of 0.8–2.1 A/m, high saturation magnetization of 0.80–0.86 T, high compressive yield strength of 2970–3076 MPa, and large plastic strain of 1.9–2.1%. The mechanisms of the high GFA and good magnetic softness of the alloys were discussed.

Bulk metallic glass composites containing in-situ formed β-Ti/Zr phases (β-type BMGCs), which exhibit a good combination of strength and plasticity, were generally developed by adding β-stabilizers, such as Nb, Ta, V, etc., into Ti/Zr-based bulk metallic glasses (BMGs). In this work, an iteration method is proposed to develop β-type BMGCs from Ti/Zr-based BMGs, and the compositions of BMGCs can be designed by “the composition of in-situ formed β phase (the iterative variable) + the composition of BMG”. Due to the fast elemental diffusions between the β phase and the (supercooled) liquid phase, the iteration method can develop β-type BMGCs in which both phases can maintain a mutual (metastable) equilibrium during solidification. The procedures of the iteration method and its underlying thermodynamic and kinetic principles are discussed, and a Zr56.9Ti18.8Cu7.4Ni5.7Be11.3 BMGC was developed from Vitreloy 1 by using the iterative method. As compared with β-type BMGCs developed by the conventional method, β-type BMGCs developed by the iteration method have two advantages: (i) the good glass-forming ability of the initial BMGs can be largely inherited by the glassy matrices in BMGCs; (ii) without adding β-stabilizers, the in-situ formed β phases are more likely to be metastable. The current iteration method is of scientific significance on improving plasticity of Ti/Zr-based BMGs and developing new β-type BMGCs.

A novel series of in-situ dendrite Ti-based bulk metallic glass composites (BMGCs) were obtained. The Mo content of the dendrites monotonically increases from nil to 10.5 at% while the dendrite volume fraction and the composition of the amorphous matrix remain nearly invariant. It was found that the mechanical behaviors varied tremendously simply by changing the Mo content. Thus, the correlation between the composition and the mechanical behaviors under tension has been determined for in-situ dendrite Ti-based BMGCs for the first time.

Nano-scale compositional heterogeneity of crystalline phase in Ti-based amorphous alloy composites (AACs) has been successfully tuned by tuning cooling rate in solidification process. And the effect of compositional heterogeneity on the kinetics of the deformation-induced phase transformation was investigated by in-situ synchrotron-based high-energy X-ray diffraction (HE-XRD) and ex-situ transmission electron microscopy. In-situ HEXRD experiments provide obvious evidence that with the decrease of the cooling rate during solidification, the critical stress of the deformation-induced phase transformation becomes lower, and the phase transformation rate becomes higher. Further high angle annular dark field-scanning electron microscopy investigation shows that the occurrence of the nano-scale Zr-lean compositional heterogeneity, which can favor the nucleation of the martensite, is the reason for the variation of the phase transformation kinetics.

Martensitic transformations originate from a rigidity instability, which causes a crystal to change its lattice in a displacive manner. Here, we report that the martensitic transformation on cooling in Ti–Zr–Cu–Fe alloys yields an amorphous phase instead. Metastable β-Ti partially transforms into an intragranular amorphous phase due to local lattice shear and distortion. The lenticular amorphous plates, which very much resemble α′/α″ martensite in conventional Ti alloys, have a well-defined orientation relationship with the surrounding β-Ti crystal. The present solid-state amorphization process is reversible, largely cooling rate independent and constitutes a rare case of congruent inverse melting. The observed combination of elastic softening and local lattice shear, thus, is the unifying mechanism underlying both martensitic transformations and catastrophic (inverse) melting. Not only do we reveal an alternative mechanism for solid-state amorphization but also establish an explicit experimental link between martensitic transformations and catastrophic melting., Displacive martensitic transformations through lattice distortion usually involve a change from one crystal structure to another. Here however, the authors “melt” metastable Ti alloys during cooling and show that a martensitic transformation can lead to the formation of an intragranular amorphous phase.

Minor element addition will be considered to modulate the atomic structures of materials to achieve surface activation for enhancing catalytic capability. Herein, Ag minor alloying enhances the catalytic behaviors of Cu-Zr-Al MGs in degrading dye molecules due to in situ formed Cu-Ag nanocomposites as highly efficient and stable catalysts. The higher degradation efficiency and faster reaction rate for Cu46Zr44.5Al7.5Ag2 ribbons than those of Cu47.5Zr46Al6.5 ribbons are accurately achieved more than 99% efficiency and 0.32 min−1 reaction rate within 20 min after 30th run. The thermal activation energy barrier (ΔE) of 5.97 kJ mol−1 for Cu46Zr44.5Al7.5Ag2 ribbons is lower than that of 8.47 kJ mol−1 for Cu47.5Zr46Al6.5 ribbons. The enhanced capability can be attributed to the corrosion engineering and electrochemical principle, the inclusion of Ag as a cathode contributes to forming a micro-electric couple with Cu as an anode to generate a variety of active copper-based nanocomposites due to surface modification. More importantly, introducing Ag atom can promote the enrichment of Cu-Ag nanocomplexes on the surface of ribbons in order to provide stronger surface activity and faster electron transfer to further improve catalytic performance. These findings are expected to help open up new functional applications of CuZr-based MGs in environment field.

It remains challenging to develop low-cost body-centered cubic (BCC) high-entropy alloys (HEAs) with superior mechanical properties. In this work, we investigated the microstructure and mechanical properties of BCC FexCrNiAl0.5Ti0.5 HEAs containing L21 nanocrystals. With increasing the Fe content from Fe2 to Fe4 and Fe6, the formation of a big blocky L21 phase and a σ phase can be fully suppressed, and the size and fraction of the L21 crystals also decrease. Fe4 and Fe6 HEAs exhibit an optimized dual-phase microstructure with high-density L21 nanocrystals homogeneously distributed in the BCC matrix. Fe4 and Fe6 HEAs show high strength and do not fracture even at a large compressive strain of 70%, exhibiting the best combination of strength and fracture strain among all the reported BCC HEAs with nanocrystals. The superior mechanical properties of Fe4 and Fe6 HEAs are attributed to the optimized microstructure. These findings promote the development of low-cost HEAs with superior mechanical properties.

A high-entropy alloy Fe10Co10Ni10Cr10Mn60 ribbon catalyst with a face-centered cubic structure was designed by using Co and Ni as the main catalytic elements and combining various co-catalytic elements, such as Fe, Mn, and Cr. Substantial element selective corrosion occurs during the acid solution corrosion process, which induces the exposure of many Co and Ni atoms, increases the specific surface area, and further results in the formation of many vacancies and dislocations. This unique structure generates a positive electron effect, that is the peaks of Ni2p3/2 and Co2p3/2 shift to lower binding energies, namely, approximately 1 eV for Ni and 0.8 eV for Co, indicating the Co and Ni enrich electrons. The catalyst shows an excellent catalytic performance for the hydrolysis of NaBH4 after corrosion for 90 s, whose hydrogen production rate approaches 18.46 l/(m2·min). This work opens up a direction for the application of the macroscopic scale high-entropy alloy in the catalytic hydrogen field.

Fe-based amorphous alloys show great potential in degrading azo dyes and other organic pollutants, and are widely investigated as a kind of environmental-friendly materials for wastewater remediation. In this paper, the effects of Co, Ni or Cr addition on the decolorization properties of Fe-Si-B amorphous alloys were studied, and the mechanism of their different effects was analyzed. Co addition could lower the activation energy of Fe-Si-B amorphous alloys in decolorizing azo dyes, and had no weakening effect on the decolorization capability of Fe-Si-B amorphous alloys. Ni addition led to partial crystallization of Fe-Si-B amorphous alloys, and the decolorization mechanism at low temperatures changed from chemical degradation to physical adsorption. Cr addition could enhance the corrosion resistance of Fe-Si-B amorphous alloys, but the amorphous alloys completely lost the decolorization capability no matter at lower or higher temperatures. The results of X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) indicated that the addition of Co, Ni or Cr could generate different surface structures that had significant influences on the decolorization process. Our work demonstrated that the effiecient decolorization of azo dyes by Fe-based alloys could be realized only when amorphous nature and incompact surface structure were simultaneously achieved for the alloys.

The mechanism and kinetics of acid orange II (AOII) treated by aged gas-atomized Fe-Si-B metallic glass (MG) powders were investigated in this study. The decolorization reaction is shown to obey the pseudo-first-order kinetic model, and the treatment processes could be divided into two stages: a slow step followed by a rapid one. This observation is in accordance with the following results, the azo dye is simply adsorbed onto the Fe-based MG powders in the initial stage, because the oxide layer coated on the powder surface depresses the degradation reaction by covering the activity sites, and then the degradation occurs with the desquamation of the powders. The AOII could be degraded with a rapid reaction rate when the Fe-based MG powders are applied to the treatment process again, because of the consumption of the oxide layer and the unchanged core of the Fe-based MGs. These findings will promote the practical application of MGs in degrading azo dyes.

In order to obtain a glassy matrix during quenching, Be is often selected as a constituent of the compositions of Ti/Zr-based bulk metallic glass composites (BMGCs). The in situ formed β phase in Be-bearing BMGCs was reported to be Be-free. However, a thorough investigation of the distribution of Be in BMGCs is still missing to date. In this work, the distribution of Be in a Ti 47.5 Zr 33 Cu 5.8 Co 3 Be 12.5 (at.%) BMGC was studied by the secondary ion mass spectrometry (SIMS) and the electron energy loss spectroscopy (EELS). It is found that Be almost totally dissolves in the glassy matrix, but a very weak intensity of Be in β phase is still detectable by SIMS, and the content of Be in β-Ti is estimated to be about 0.3 at.%. Based on the recently established two-phase quasi-equilibrium of BMGCs, the distinct solubility of Be in the glassy matrix and in β-Ti has been explained.

Addition of a small amount of La and Co enhances the stabilization of supercooled liquid and glass-forming ability (GFA) of an Al85Ni7Er8 metallic glass. The Al85Ni5Co2Er6La2 alloy exhibits large supercooled liquid region of 40 K, high GFA with a critical thickness of 450 μm, and the viscosities on the order of 107−109 Pa s in the supercooled liquid state. The Al-based glassy nano-scale patterns were formed by imprinting, indicating its good thermoplastic formability. The possible mechanism for the improvement of the supercooled liquid stability of the Al Ni Er alloy by addition of La and Co elements was discussed in terms of the crystallization behavior.

Ti/Zr-based bulk metallic glass composites (BMGCs) containing an in-situ formed β phase (β-type BMGCs) normally show a poor work-hardening capability or even work-softening during plastic deformation. The limited work-hardening capability of the β phase by the entanglement of dislocations cannot totally compensate the shear softening of the glassy matrix. In this work, a strategy is proposed to destabilize the β phase, and the BMGC containing a metastable β phase (metastable β-type BMGC) shows improved plasticity and work-hardening capability due to the deformation-induced phase transformation from β-Ti to α″-Ti. The underlying principle for destabilizing β phases in BMGCs by adjusting the overall compositions and the structural origins for the improved plasticity and work-hardening capability of metastable β-type BMGCs are discussed. These findings shed light on developing metastable β-type BMGCs with excellent mechanical properties.

Soft magnetic Co-based bulk metallic glasses (BMGs) with large supercooled liquid region (ΔTx) and high saturation magnetic flux density (Bs) have been developed in a new Co–Fe–Y–B alloy system. Addition of appropriate contents of Y and Fe into a Co75B25 alloy enlarges the ΔTx and improves the glass-forming ability (GFA). ΔTx of 50–64 K and a critical diameter of up to 2.0 mm have been achieved for the (Co0.5–0.7Fe0.3–0.5)71.5Y3.5B25 BMGs. The coercivity (Hc) of Co75-xYxB25 and (Co0.7Fe0.3)75-xYxB25 (x = 0–5) alloy series shows a similar V-shape change with Y content, and gets the minimum at x = 3.5, while that of (Co1-yFey)71.5Y3.5B25 (y = 0–0.5) alloys keeps rising with the increase of Fe content. The Bs of the alloys monotonically decreases with more Y addition and increases with enriching of Fe. The (Co0.5–0.7Fe0.3–0.5)71.5Y3.5B25 BMGs exhibit high Bs of 1.00–1.17 T and low Hc of 5.4–6.4 A/m. The BMGs possess high yield strength of 3978–4152 MPa with distinct plastic strain of up to 0.9% and Vickers hardness of 1218–1233 as well. The possible mechanisms of Y and Fe affecting the GFA, thermal stability, and magnetic properties of the Co-based Co–Fe–Y–B metallic glasses have been discussed.

In order to expand the application of Zr-based bulk metallic glasses (BMGs) in the field of biomaterials, it is vital to investigate their corrosion behaviour in different solution environments. However, until now, the corrosion behaviour of Zr-based BMGs in F−-containing solution has been rarely studied, and the corrosion mechanism is not fully understood. In this study, the effect of pH and NaF addition on the corrosion behaviour of Zr52Al10Ni6Cu32 BMG in Na2SO4-containing solution has been investigated by employing the standard electrochemical methods. The relationship between the critical pF value and pH has been subsequently obtained, which provides a criterion for judging the state of corrosion of Zr-based BMGs in F−-containing solution. The cathodic reaction mainly involves the reduction of the dissolved oxygen in the solution, and the kinetic mechanism is similar to that of pure Zr. An oxidation peak appearing during the upward polarization scanning is attributed to the active dissolution of Cu caused by SO42− and F−. During upward polarization, different pH values and addition of NaF are observed to result in consequent film breakdown behaviour. For 0.1 M NaF and pH = 8.0, the protective ZrO2 passive film is noted to be replaced by the corrosion product of the Zr–F compound. However, at pH = 4.0 with 0.001 M NaF, the F− concentration is not sufficient to form the Zr–F corrosion products, and the dissolution rate of the passive film is enhanced due to the reduced pH. This study provides a deeper understanding of the corrosion mechanism of Zr-based BMGs alloys in F−-containing solution.

To circumvent the trade-off with plasticity and strength, a series of TiZr-based controllable multilayered bulk metallic glass composites (ML-BMGCs), with ex-situ Ti layers and glassy matrix containing precipitated dendrites distribution in an alternate, was fabricated by the hybrid strategy with in-situ and ex-situ. ML-BMGCs exhibit not only enhanced plasticity from 1±0.2% to 8.4±0.2% but also improved the fracture strength from 1643±15 MPa to 1956±20 MPa under compression. The improved strength is attributed to that the solid solution strengthen of Zr in the ex-situ Ti layers by Zr element diffusion from glassy matrix to them is increasing with Zr addition. Ti layers and the in-situ dendrites create a strong barrier for the shear band propagation and generate multiplies of the shear band after solid solution strengthening, thereby which together with the pronouncedly plastic deformation of Ti layers, greatly improves the plastic deformation capacity.

The amorphous catalysts can be electrochemically activated to expose active sites during the short-range order structure, greatly increasing the number of active sites and thus significantly improving the water oxidation activity. Herein, we developed disordered sandwich-like multi-layer structure with abundant oxygen vacancies as a highly excellent electrocatalyst for the oxygen evolution reaction (OER), which was derived from amorphous Ni40Fe40B20 ribbons precursors through in situ hydroxylation and electro-oxidation in alkaline solution. The as-fabricated product shows the low overpotential of 249 mV and 338 mV at a current of 10 mA·cm−2 and 250 mA·cm−2 with a Tafel slope of 43 mV·dec−1, respectively. This excellent catalytic performance is attributed to the synergistic effect resulted from the hybrid composition of disordered α-Ni(OH)2 and γ-FeOOH, excellent electron/mass transfer due to the presence of abundant oxygen vacancies and expandable actual surface area. Moreover, the catalysts after structural reconstruction still maintain good flexibility, which is good for industrial applications. This work may provide insight into the combination of disordered structure and oxygen vacancies through in situ grown on amorphous alloys and make them as promising industrial OER electrocatalysts.

The Ti 36.2 Zr 30.3 Cu 8.3 Fe 4 Be 21.2 (at.%) bulk metallic glass (BMG) exhibits a regular micrometer-sized pattern in the transmission electron microscope (TEM) after ion milling. Quantitative energy-dispersive X-ray spectroscopy (EDX) results show that the compositions in the bright and dark regions are distinctly different, and the compositions gradually change with the contrast of the pattern. In the intermediate regions (with grey contrast) preferential crystallization is observed and this confirms that microscale heterogeneities exist in the ion-milled TEM specimens. On the contrary, the specimens prepared by focused ion beam and by electrolytic thinning show featureless microstructures in the TEM. Moreover, EDX results and the secondary ion mass spectroscopy show that the constituent elements are homogeneously distributed. An ion milling-induced compositional fluctuation mechanism is proposed, and the partial devitrification can be explained based on this mechanism. The present findings may lead to a deeper understanding of the occurrence of micrometer-sized heterogeneities in BMGs induced by ion milling.

Co-based (Co, Fe)75B15Si7P3 bulk metallic glasses (BMGs) without any early transition metal or rare-earth elements have been successfully developed, which possess outstanding soft magnetic properties with high saturation magnetic flux density (Bs) and good mechanical properties. Addition of an appropriate amount of P into a Co75B15Si10 alloy promotes the occurrence of glass transition and increases the stability of the supercooled liquid, and a Co75B15Si7P3 metallic glass exhibits a large supercooled liquid region of 33 K. Subsequent replacement of Co by 15–35 at.% Fe enhances the glass-forming ability (GFA) of the Co75B15Si7P3 alloy, and the BMG rods with diameters up to 2.0 mm are obtained. The improved GFA might be originated from the high thermal stability of the alloy melts as indicated from the large undercoolings. The Co-based (Co, Fe)75B15Si7P3 BMGs possess low coercivity of 0.8–4.6 A/m, high Bs of 1.02–1.24 T, effective permeability of 12700–18500 at 1 kHz, and Curie temperature of 739–789 K, indicating superior soft magnetic properties compared to other reported Co-based BMGs. The BMGs also exhibit high compressive yield strength of 3343–3590 MPa with distinct plastic strain up to 2.7% and high Vickers hardness of 1150–1175. The combination of high GFA and excellent soft magnetic and mechanical properties makes the Co-based BMGs a good prospect of functional materials.

The strain rate effect on the mechanical behavior of amorphous alloys has aroused general interest. Most studies in this area have focused on quasi-static and high strain-rate compressive deformations. However, experimental results have been few, or even non-existent, under a moderate strain-rate loading. This article extends the traditional split Hopkinson pressure bar (SHPB) technique to characterize compressive deformation of an amorphous alloy at medium strain rates. The compressive behavior of Zr65.25Cu21.75Al8Ni4Nb1 amorphous alloy shows a negative strain rate effect on the yield strength with a quasi-static, moderate to high strain-rate range, and the fracture angle increases from 44&deg, at 10&minus, 5 s&minus, 1 to 60&deg, at 4000 s&minus, 1 as strain rate increases. Herein, we introduce a modified cooperative shear model to describe the compressive behavior of the current amorphous alloy under a broad strain rate range. The model predicts that the normalized yield strength will linearly descend with logarithmic strain rate when the strain rate is less than a critical strain rate, however, which rapidly decreases linearly with the square of the strain rate at high strain rates. The predicted data of the model are highly consistent with the current experimental results. These findings provide support for future engineering applications of amorphous alloys.

Tungsten fibre/Zr-based bulk metallic glass matrix composite (WF/Zr-MG) is a potential penetrator material. In the present paper, the effect of L/D on the penetration performance of WF/Zr-MG rod is studied. Experiments and finite element method (FEM) simulations of WF/Zr-MG and tungsten heavy alloy (WHA) rods with L/D of 18.33, 5.4, 3.89, 3.75 and 1.11 penetrating into armor steel targets (RHA) are conducted. The experimental results show that penetration efficiency (P/L) of WF/Zr-MG rods with L/D of 18.33, 5.4, 3.89 are higher than that of WHA rods with the same L/D, because the penetration process is long enough to include a steady state penetration self-sharpening. The steady state penetration self-sharpening results in less kinetic energy consumed of rods during penetration. Longitudinal splitting occurs in WF/Zr-MG rods with L/D of 3.75 during the penetration process, which results in a much lower P/L than that of WHA rods with L/D of 3.75. A jacket structure could prevent the longitudinal splitting and increase P/L of WF/Zr-MG rods. P/L of jacketed WF/Zr-MG rods with L/D of 1.11 is slightly lower than that of jacketed WHA rods with L/D of 1.11, because of its short penetration process without the steady state penetration self-sharpening. P/L curve fitted as a function of normalized impact velocity and L/D of the WF/Zr-MG rods into RHA shows the advantages of WF/Zr-MG rods over WHA rods increase with L/D.

Aimed at developing new Ni-free Zr-based bulk metallic glasses (BMGs), a series of Ni-free Zr–Al–Fe–Cu glass formers have been developed in this work. The compositions are designed by using a combination of clusters and mixing entropy. Glass formers in this system are considered to be a mixture of Zr–Al, Zr–Fe and Zr–Cu clusters. Their coefficients were obtained by the calculation of mixing entropy. Under the guidance of this method, a series of compositions with high glass forming ability (GFA) were developed. Among the glass formers, the alloy compositions of Zr 60.32 Cu 22.56 Fe 9.95 Al 7.17 and Zr 64.08 Cu 18.78 Fe 10.02 Al 7.12 possess the highest GFA. Glassy rods can be fabricated at these two compositions with critical diameter up to 5 mm, which is superior to that reported for the known Zr 60 Cu 25 Fe 5 Al 10 BMG under the same condition.

A new method was proposed to pinpoint the compositions with good glass forming ability (GFA) by combining atomic clusters and mixing entropy. The clusters were confirmed by analyzing competing crystalline phases. The method was applied to the Zr–Al–Ni–Cu–Ag alloy system. A series of glass formers with diameter up to 20 mm were quickly detected in this system. The good glass formers were located only after trying 5 compositions around the calculated composition. The method was also effective in other multi-component systems. This method might provide a new way to understand glass formation and to quickly pinpoint compositions with high GFA.

The stress–strain relations for the Zr53.5Cu26.5Ni5Al12Ag3 bulk metallic glass (BMG) over a broad range of temperatures (room temperature to its supercooled liquid region) and strain rates (10−4 to 10−1 s−1) were established in uniaxial compression using a thermal-mechanical simulation system. The superplastic flow was seen above its glass transition temperature (Tg = 694 K) and strain rates of up to 10−1 s−1 from the variation of stress–strain curves. A deformation map of strain rate vs temperature of Zr53.5Cu26.5Ni5Al12Ag3 was obtained, which was mainly composed of homogeneous and inhomogeneous deformation regions, the former featuring either Newtonian or non-Newtonian flow while the latter characterizing linear elastic behavior followed by shear localization, respectively. A phenomenological constitutive equation used to describe a master curve of viscosity with respect to the strain rate was obtained by fitting the experimental results, which determines the viscosity of the present alloy at the temperature near and above Tg. The results show the Zr53.5Cu26.5Ni5Al12Ag3 BMG is the subject suitable for net shape forming process at the supercooled liquid region.

The galvanic corrosion of the coupled Al2Cu and Al as well as Al3Fe and Al in 0.005 M NaCl in and without the presence of cerium cinnamate was studied. Scanning vibrating electrode technique and scanning ion-selective electrode technique were used to measure the distribution of current densities and pH. The results indicate that cerium cinnamate played inhibiting effect on the coupling corrosion of Al2Cu–Al and Al3Fe–Al. For Al2Cu–Al, the inhibition was mainly influenced by the production of cerium oxide/hydroxide on Al2Cu surface. However, for Al3Fe–Al, the inhibition was mainly influenced by the adsorbed cerium cinnamate on the Al3Fe surface.

The tensile properties and deformation behaviors of Zr based metallic glass composites containing different tungsten fiber orientations were investigated. The angles (θf) between tungsten fiber orientation and loading axial direction are 0°, 15°, 30°, 45°, 60°, 75° and 90°, respectively. The results show that the strength and the failure modes vary with θf. The tensile strength of the composite decreases as the θf increases. The tensile strength of the composite at θf=90° is only 253 MPa. The plasticity of all the composites do not be improved. The composites failed approximately 90° normal fault at θf=0°/15°, while the composites failed along the tungsten fiber when the θf is bigger than or equal to 30° because of the low axial grain boundary strength of the elongated W grains.

Electrochemical performance of the as-prepared silicon based composite electrode for lithium ion battery can be enhanced by modifying the surface morphology of the Cu foil used as the anode current collector. Increasing the roughness of the Cu foil, contributes to the strong interface adhesion between the anode current collector and the silicon based active composite material slurry layer. The electrode with surface morphology modified Cu current collector delivers higher specific capacity and exhibits better rate capability than that with unmodified Cu current collector. It is also found that the cycle-life of the silicon based composite electrode has been significantly improved by using a surface morphology modified anode current collector. The enhanced cyclability is attributed to the good electrical contact integrality between the active materials and the anode current collector. The improved electrochemical performance indicates that optimizing the anode current collector system can be a valuable alternative for improving electrochemical properties of lithium ion rechargeable batteries.

High strength aluminum (Al) alloys were prepared by rapid solidification method in the Al–Ni–La system. Microstructural characterizations show that all the investigated Al–Ni–La alloys are comprised of Al, rod-like Al3Ni, and blocky Al11La3 phases, of which the size and volume fraction are composition-dependent. The Al85.5Ni9.5La5 (at.%) alloy shows the finest microstructure, which contributes to the highest strength along with considerable plasticity. The experimental analysis and finite element simulation (FES) show that the distribution of the intermetallic phases greatly affects the mechanical properties of the alloys. The rod-like Al3Ni phase precipitated with the locally uniform direction prevents the propagation of cracks and benefits the plastic deformation, whereas the blocky Al11La3 phase exhibits the nature of brittleness and acts as the origin of the microcrack initiation. These findings suggest a new method to design high strength Al alloys.