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Lunar glasses with different origins act as snapshots of their formation processes, providing a rich archive of the Moon's formation and evolution. Here, we reveal diverse glasses from Chang’E-5 (CE-5) lunar regolith, and clarify their physical origins of liquid quenching, vapor deposition and irradiation damage respectively. The series of quenched glasses including rotation-featured particles, vesicular agglutinates and adhered melts, record multiple-scale impact events. The abundant micro impact products, like micron to nano-scale glass droplets or craters, highlight that the regolith is heavily reworked by frequent micrometeorite bombardment. Distinct from Apollo samples, the indigenous ultra-elongated glass fibers drawn from viscous melts and the widespread ultra-thin deposited amorphous rims without nanophase iron particles both indicate a relatively gentle impact environment at the CE-5 landing site. The clarification of multitype CE-5 glasses also provides a catalogue of diverse lunar glasses, making more Moon's mysteries recorded by glasses capable to be deciphered in future.

Volatiles transport in the lunar regolith is essential for lunar soil evolution and in-situ resources utilization (ISRU) and has not been fully understood. Here, we characterize a typical agglutinate particle from Chang’E-5 samples and demonstrate the transport behavior of volatiles through the porous structure. The results of surface and 3D structural characterization indicate that the formation of the smooth porous structure is mainly caused by volatiles flow. Based on the element distribution analysis, we further speculate the main component of the volatiles is gas water attributed to the reduction of FeO by abundant hydrogen in the superficial lunar regolith during micrometeoroids impacts. Numerical models of volatiles (gas water) transport in the porous agglutinate have been developed for different pressure conditions. The results show the ultrafast transport of volatiles makes the superficial regolith dry and barren under high-vacuum condition. We conclude that rapid escape of volatiles can hardly retain water in the superficial lunar soil yet provides opportunities for development of ISRU technology.

In-space manufacturing is an emerging and promising research field in space industry, which benefits the development of space explorations. Owing to the microgravity, high vacuum and complexity of the space environment, a special manufacturing strategy for alloys is highly demanded for the in-space manufacturing. Herein, a low-temperature thermoplastic metallic welding method was proposed and employed for La-based metallic glass ribbons. With the sandwiched structures of La- and Zr-based ribbons, the welded samples exhibit a competitive fracture strength and an increased tensile strain than those of the welded la-based samples due to the second phase strengthening. This suggests that metallic glass is an ideal material candidate for in-space manufacturing, and can be well manufactured at a nonmelting state with good mechanical performances. In addition, the thermoplastic manufacturing method can also feature a moderate processing time window. In general, this work presents the promising potential of low-temperature thermoplastic welding strategy for in-space manufacturing of metallic materials.

Since their discovery in 19601, metallic glasses based on a wide range of elements have been developed2. However, the theoretical prediction of glass-forming compositions is challenging and the discovery of alloys with specific properties has so far largely been the result of trial and error3–8. Bulk metallic glasses can exhibit strength and elasticity surpassing those of conventional structural alloys9–11, but the mechanical properties of these glasses are critically dependent on the glass transition temperature. At temperatures approaching the glass transition, bulk metallic glasses undergo plastic flow, resulting in a substantial decrease in quasi-static strength. Bulk metallic glasses with glass transition temperatures greater than 1,000 kelvin have been developed, but the supercooled liquid region (between the glass transition and the crystallization temperature) is narrow, resulting in very little thermoplastic formability, which limits their practical applicability. Here we report the design of iridium/nickel/tantalum metallic glasses (and others also containing boron) with a glass transition temperature of up to 1,162 kelvin and a supercooled liquid region of 136 kelvin that is wider than that of most existing metallic glasses12. Our Ir–Ni–Ta–(B) glasses exhibit high strength at high temperatures compared to existing alloys: 3.7 gigapascals at 1,000 kelvin9,13. Their glass-forming ability is characterized by a critical casting thickness of three millimetres, suggesting that small-scale components for applications at high temperatures or in harsh environments can readily be obtained by thermoplastic forming14. To identify alloys of interest, we used a simplified combinatorial approach6–8 harnessing a previously reported correlation between glass-forming ability and electrical resistivity15–17. This method is non-destructive, allowing subsequent testing of a range of physical properties on the same library of samples. The practicality of our design and discovery approach, exemplified by the identification of high-strength, high-temperature bulk metallic glasses, bodes well for enabling the discovery of other glassy alloys with exciting properties. Bulk metallic glasses made from alloys of iridium, nickel, tantalum and boron are developed by combinatorial methods, with higher strength at high temperature than those previously produced.

Conductive polymer composites have been applied in temperature sensing owing to its resistance response to temperature change. In this work, composites with short carbon fibers (CFs) filled in silicon rubber (SR) were 3D printed. The positive temperature coefficient (PTC) effect of the composite resistance behaved anisotropically due to the CFs’ orientation, where the PTC intensity was lower when tested along the CFs’ orientation than that along other directions. The composites owned an excellent PTC effect reproducibility at the temperature of 25 ~ 100 °C. In-situ observation shows that the CFs in the composites shifted about 2.62 ± 1.05 μm when the temperature increased from 25 °C to 80 °C. The resistance creep under isothermal aging treatment reveals that the composites could keep their resistance relatively stable at the isothermal aging of 20 ~ 80 °C. The mechanical loads could help the crept resistance to recover to its original value very quickly, which was referred to resistance memory effect (RME) in this article. CF/SR composite was finally connected into circuits as thermistor and temperature sensor, which verified a potential application for temperature sensing.

Helium-3 (3He) is a noble gas that has critical applications in scientific research and promising application potential as clean fusion energy. It is thought that the lunar regolith contains large amounts of helium, but it is challenging to extract because most helium atoms are reserved in defects of crystals or as solid solutions. Here, we find large amounts of helium bubbles in the glassy surface layer of ilmenite particles that were brought back by the Chang’E-5 mission. The special disordered atomic packing structure of glasses should be the critical factor for capturing the noble helium gas. The reserves in bubbles do not require heating to high temperatures to be extracted. Mechanical methods at ambient temperatures can easily break the bubbles. Our results provide insights into the mechanism of helium gathering on the moon and offer guidance on future in situ extraction.

Direct measurement of critical cooling rates has been challenging and only determined for a minute fraction of the reported metallic glass forming alloys. Here, we report a method that directly measures critical cooling rate of thin film metallic glass forming alloys in a combinatorial fashion. Based on a universal heating architecture using indirect laser heating and a microstructure analysis this method offers itself as a rapid screening technique to quantify glass forming ability. We use this method to identify glass forming alloys and study the composition effect on the critical cooling rate in the Al–Ni–Ge system where we identified Al51Ge35Ni14 as the best glass forming composition with a critical cooling rate of 104 K/s.

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.

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

Metallic glasses are perfect materials for preparing nanostructures by dealloying, but the obtained nanostructures are commonly of porous structures. Through the combination of chemical dealloying and ultrasonic vibration, ultrathin Cu&Ag bimetallic nanoporous membranes (NPMs) have been prepared from a Zr48Cu36Ag8Al8 MG ribbon. Furthermore, by introducing oxygen into the Zr48Cu36Ag8Al8 MG ribbon to change the mechanism of the dealloying process, nanoporous (Cu&Ag)@Ag core-shell alloy was synthesized by the one-pot chemical dealloying of Zr–Cu–Ag–Al–O amorphous/crystalline composite, which provides a new way to prepare metallic core–shell nanostructures by a one-pot method. The introducing of oxygen can enable the dissolution and redeposition of Cu, and tunes the Cu&Ag NPM into the nanoporous (Cu&Ag)@Ag core-shell alloy. The nanoporous (Cu&Ag)@Ag core-shell alloy exhibits better and robust antibacterial activity against E. Coli DH5α due to its better oxidation resistance caused by the Ag skin. The present work provides important insights into the tuning of nanostructures through simple dealloying.

The Ti-based bulk metallic glasses (BMG) with high Ti content (>50 at.%) have attracted wide attention for their outstanding mechanical properties, despite their glass forming ability (GFA) is still relatively poor. Here the (Ti 55 Zr 15 Be 20 Ni 10 ) 100-x Cu x (x = 2, 4, 6, 8 and 10 at.%) BMGs were designed and prepared by copper mold casting. The critical diameter of the original alloy could be enhanced from 5 mm to 10 mm with the Cu addition of 4 at.%, which is the first reported centimeter-sized Ti-based BMG with Ti content more than 52 at.%. In addition, all the as-prepared BMGs exhibited higher yield strength (above 2000 MPa). And the supercooled liquid range of the as-prepared Ti-based BMGs were enlarged from 35 K to 74 K by Cu addition. Electrochemical measurements showed that the BMGs with Cu addition of 0–6 at.% exhibited much higher pitting potentials (over 573 mV/SCE) than that of 304 stainless steel (304SS) in 3.5 wt% NaCl aqueous solution. And The XPS analysis revealed that the Cu addition might lead to the enrichment of Cu and the deficiency of Ti, Zr, Ni elements in passive film, which could induce the worse corrosion resistance of the Ti-based BMGs with high Cu content. The results indicate that the developed Ti-based BMGs possess good GFA, mechanical properties and corrosion resistance.

Photodetectors based on low-dimensional materials have attracted tremendous attention because of their high sensitivity and compatibility with conventional semiconductor technology. However, up until now, developing low-dimensional phototransistors with high responsivity and low dark currents over broad-band spectra still remains a great challenge because of the trade-offs in the potential architectures. In this work, we report a hybrid phototransistor consisting of a single In2O3 nanowire as the channel material and a multilayer WSe2 nanosheet as the decorating sensitizer for photodetection. Our devices show high responsivities of 7.5 × 105 and 3.5 × 104 A W–1 and ultrahigh detectivities of 4.17 × 1017 and 1.95 × 1016 jones at the wavelengths of 637 and 940 nm, respectively. The superior detectivity of the hybrid architecture arises from the extremely low dark currents and the enhanced photogating effect in the depletion regime by the unique design of energy band alignment of the channel and sensitizer m...

With Ti addition in a NbMoTaW alloy, a new refractory high entropy alloy (HEA) of TiNbMoTaW was developed. It has been found that this HEA possesses single body-centered cubic (BCC) phase structure, and could sustain the phase structure even after annealing at 1200 °C for 24 h. In comparison with the mechanical properties of the NbMoTaW and VNbMoTaW HEAs, the room-temperature yield strengths and compressive plastic strains of the TiNbMoTaW and TiVNbMoTaW HEAs are significantly enhanced. In particular, the TiNbMoTaW and TiVNbMoTaW HEAs also show very promising high temperature strength. Their yield strengths are as high as ∼586 and ∼659 MPa at 1200 °C, respectively. The present results indicate that Ti addition is beneficial to the strength and the compressive ductility of the refractory HEAs at room-temperature. It is suggested that the present refractory HEAs possess the potentials in applications of high temperature structure materials.

The effect of fluxing treatment on the properties of Fe66Co15Mo1P7.5C5.5B2Si3bulk amorphous alloy (BAA) has been investigated. Prepared by a combination method of flux treatment and water quenching, the Fe66Co15Mo1P7.5C5.5B2Si3 BAA exhibits better glass-forming ability, thermal stability, soft magnetic properties and ductility than those of the one prepared by direct water quenching. This indicates that fluxing treatment can play a potential role in improving the properties of Fe-based BAA due to the effective elimination of the impurities within the alloy.

Laser cladding provides a widely applicable method for the preparation of metallic glass matrix composite (MGMC) coatings, where the mechanical property and the corrosion resistance can be tailored by the in-suit precipitated crystalline phases. Thus, the investigation on the microstructure evolution and corrosion mechanism of MGMC coating to achieve superior performance is of great importance. In the presented work, Zr50.7Cu28Ni9Al12.3 MGMC coatings, which are constituted by Zr&Cu enriched dendrites and Ni&Al enriched metallic glass (MG) matrix, were prepared by laser cladding. The effect of the laser power on the microstructure and the corrosion property of the MGMC coatings was investigated. It has been found that the MG content increases and the size of the dendrites decreases with decreasing laser power. Increasing MG content in the coating can decrease the self-etching current density due to the rapid surface oxidation, and decrease the open-circuit-potential due to the higher chemical activity of MG. Besides that, a probable corrosion mechanism of the Zr-Cu-Ni-Al MGMC coating in the NaCl solution was proposed. The segregation of Cu could be the main inducement for pitting. The increasing MG phase content can suppress the segregation of Cu and therefore increase the pitting corrosion resistance of the coating.

We present a statistical study of serration behaviours in Pd77.5Cu6Si16.5, Ti41Zr25Be26Ag8, Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 and Fe50Ni30P13C7 metallic glasses with different plasticity. The four samples show similar serration patterns in the beginning of yielding, and different patterns during later loading. These results indicate that the shear band initiation process in metallic glasses follow some similar dynamics. And the later serration process follows different dynamics and will lead to different plasticity. Here we interpret these serration behaviours from a perspective of inhomogeneity. The different serration patterns and shear band dynamics could be reasonably understood. The serration pattern of the Fe-based sample suggests that the brittleness of metallic glasses might result from a lower degree of inhomogeneity, and a less tendency of forming shear band intersections. This study might provide new experimental evidences for different micro-structures (or inhomogeneity) and dynamic behav...

A series of pseudo-quinary Ti20Zr20Hf20Be20(Cu20-xNix) (x = 2.5, 5, 7.5, 10, 12.5, 15, 17.5 and 20 at.%) high entropy bulk metallic glasses (HE-BMGs) with large glass forming ability (GFA) were successfully prepared by copper mold tilt-casing. The critical diameters (Dc) of these HE-BMGs are all above 12 mm. In particular, the developed Ti20Zr20Hf20Be20(Cu7.5Ni12.5) and Ti20Zr20Hf20Be20Ni20 high entropy alloys (HEAs) can be produced in the amorphous state with diameters up to 30 mm and 15 mm, respectively, which are the largest HE-BMG and quinary HE-BMG hitherto. The two HE-BMGs also exhibit high yield strength, together with the plastic strain values of (3.0 ± 1.1) % and (4.0 ± 0.9) %, respectively. With increasing Ni additions in the pseudo-quinary HEAs, the crystallization growth resistance and thermal stability have been improved, which is apparently due to the sluggish diffusion of the atoms in the HEAs. Keywords: Amorphous alloy, Glass-forming ability, Mechanical properties, Thermodynamic stability

While there has been significant pursuits and interest in single element metallic glass (MG), it has been extremely difficult to obtain. Despite the recent advances in preparing MGs, the massive production of stable monatomic MGs is of great challenge. Here, we show that Ta monatomic MG, presenting identical structural characteristics to those from liquid quenching, can be produced using conventional ion beam deposition on a room temperature substrate. The amorphous structure is retained even after being annealed at 573 K for 2 h, while it fully crystallizes subjected to annealing at 823 K for 5 min, corroborating the previous prediction that Ta MG is stable up to 600 K.

Flexible sensors with high sensitivity and stability have been tremendously attractive in recent years. In this study, flexible capacitive sensors (FCSs) with microstructured-surface were fabricated, where electrode layers (e-layers) and dielectric layers (d-layers) of the FCSs were sprayed with carbon fiber (CF) filled-polydimethylsiloxane (PDMS) and pure PDMS on substrate with surface roughness, respectively. Sensitivity of the fabricated FCSs to compressive load was evaluated. Influence of the surface microstructure of d - and e-layers on the sensitivity was studied through in-situ microscopic observations and theoretical capacitance calculations. Results showed that the roughness of the surface microstructure did have a correlation with the sensitivity. Excellent sensing performance, including a high sensitivity (∼0.82 kPa−1), ultrafast response (∼0.2 s) and relaxation (∼0.3 s) time, ultralow detection limit (∼1.2 Pa), and excellent stability (104 loading/unloading cycles) over a wide pressure range (0−50 kPa) appeared on the FCS with its surface microstructure size of 48.6 μm in roughness. The high sensitivity of the fabricated FCS was dominantly resulted from the closing of air gap between e- and d -layers. A 3 × 3 FCS array capable of distinguishing space pressure distribution and a mouse glove capable of inputting computer information were finally fabricated which demonstrated a prospect of the FCS in micro-load response and human-machine interaction applications.

Structural heterogeneity dominates energy-storage behavior of metallic glasses. Ti20Zr20Hf20Be20Cu7.5Ni12.5 high-entropy bulk metallic glass (HE-BMG) shows extraordinary energy-storage behavior under cryothermal cycling: the relaxation enthalpy monotonically increased with cryothermal cycling cycles, even after 240 cycles of treatment. By comparison, the relaxation enthalpy of Ti41Zr25Be22Ni12 BMGs reached a maximum only at 30 cycles and then dramatically decreased as prototypical BMGs reported. The as-cast HE-BMG demonstrates an extremely low fraction of loose-packing regions (~7.8%, fractions for Ti- and Zr-based BMGs are above 15.6%), indicating degraded structural heterogeneity that would induce smaller local internal stress during cryothermal cycling and eventually lead to the sluggish energy-storage behavior. In addition, the increase in the fraction of loose-packing regions accompanied by the energy storage also lead to significant improvement in ductility of the HE-BMG, the plastic strain increased from 0.6% (the as-cast sample) to 5.2% (the sample treated 240 cycles).

In this paper, a Laser Metal Deposition (LMD) technique has been applied to fabricate CoCrFeNiMo0.2 high-entropy alloys (HEAs). The microstructure, corrosion behavior and mechanical properties of LMD CoCrFeNiMo0.2 HEAs prepared under different laser power have been investigated. It was observed that the laser power had significant effects on the columnar crystal morphology in LMD CoCrFeNiMo0.2 HEAs. When increasing the laser power, the temperature gradient would decrease, leading to larger crystal size of columnar grains. The tensile properties at 293 K of the LMD CoCrFeNiMo0.2 HEAs could be adjusted by changing the laser power, which was corresponded to the changes of microstructure. With a decrease in temperature from 293 K to 77 K, the tensile strength and tensile ductility of the LMD 1400 W CoCrFeNiMo0.2 HEAs remarkably improved by ~70% and ~28%, to 928 MPa and 60%, respectively. In both 3.5 wt% NaCl solution and 1 mol/L H2SO4 solution, the CoCrFeNiMo0.2 exhibited higher corrosion resistance than 304 stainless steel substrate, CoCrFeNi and even lower corrosion current density than 316L stainless steel.

The glass-forming ability (GFA) of Ti–Zr–Be ternary alloys is dramatically improved by partially replacing Be with Ni. Centimeter-scale fully amorphous samples can be obtained in a wide Ni content range of 4 at.%–12 at.%. In particular, some of the developed Ti–Zr–Be–Ni alloys exhibit a critical diameter up to 20 mm, which is larger than that of other quaternary Ti-based bulk metallic glasses (BMGs). Moreover, Ni addition also enhances the yield strength and compressive plastic strain of Ti–Zr–Be alloys obviously. Based on the experimental results, the effect of substituting elements addition on the glass-forming ability of Ti–Zr–Be alloys has been systematically investigated and an empirical composition design method for the development of novel Ti-based BMGs with large GFA has been proposed. Keywords: Ti-based alloys, Bulk metallic glasses, Glass-forming ability, Mechanical properties, Thermal stability

By replacing Be with Cu in ternary Ti–Zr–Be alloys, new centimeter-sized quaternary Ti-based bulk metallic glasses (BMGs) have been successfully synthesized in Ti41Zr25Be34−xCux (x = 2, 4, 6 and 8 at. %) and Ti45Zr20Be35−xCux (x = 2, 4, 6, 8 and 10 at. %) alloys. With the Cu addition, the glass-forming ability (GFA), the supercooled liquid range and the yield strength of the ternary Ti–Zr–Be glassy alloys are obviously improved. Among all the developed glassy alloys in the present study, the Ti41Zr25Be28Cu6 BMG has a critical diameter of 15 mm, which is the largest size in the quaternary Ti-based BMGs. The experimental results show that Cu is an effective element for improving the GFA of the Ti–Zr–Be glassy alloys.

Owning to their excellent thermal stability and high strength at elevated temperature, high entropy alloys (HEAs) possess great potential for the application in aviation and aerospace fields. In present work, two novel Nb–Ni–Ti–Co–Zr and Nb–Ni–Ti–Co–Zr–Hf HEAs were prepared by arc melting and copper mold suction-casting method. The microstructure, phase stability, mechanical properties at room temperature and elevated temperature of the two HEAs were studied. Both of the HEAs possess high yield stress at room temperature, especially for the Nb–Ni–Ti–Co–Zr (with 2331 Mpa). In addition, the Nb–Ni–Ti–Co–Zr HEA exhibited high yield stress of 564 Mpa at elevated temperature of 800 °C and large compressive plastic strain (more than 50% at 800 °C). Nb–Ni–Ti–Co–Zr–Hf alloy showed new phase precipitation at 800 °C, whereas the structure of Nb–Ni–Ti–Co–Zr was more stable, which is one of the reason why it possesses high strength at room temperature and elevated temperature. The high temperature properties of the Nb–Ni–Ti–Co–Zr HEA make it promising for high temperature application.

Using copper mold suction casting, high Ti content alloys of Ti50Zr16Be24Ni10, Ti50Zr20Be20Ni10, and Ti55Zr15Be20Ni10 are fabricated in bulk metallic glasses (BMGs) with the critical diameters (Dc) of 10, 6, and 5 mm, respectively. In particular, the Ti50Zr16Be24Ni10 BMG is the first centimeter-scale high Ti content BMG with Ti concentration as high as 50 at%. In addition, these high Ti content BMGs exhibit high specific strength and apparent plastic strain. Especially, the Ti50Zr16Be24Ni10 BMG exhibits a specific strength of 3.87 × 105 N m kg−1 and a plastic strain of 5.7 ± 0.5%. Our results indicate that a combination of lower Zr and higher Be contents promotes glass formation in the Ti–Zr–Be–Ni alloy system. The developed Ti-based BMGs with high specific strength provide potentials for engineering applications.

The nonisothermal crystallization kinetics, fragility, and thermodynamics of Ti20Zr20Cu20Ni20Be20 high entropy bulk metallic glass (HE-BMG) have been investigated by differential scanning calorimetry. The activation energies for the glass transition and crystallization events were determined by Kissinger and Ozawa methods. The value of local Avrami exponent is less than 1.5 in most cases for all the three crystallization events, indicating that the major crystallization mechanism is diffusion-controlled growth of pre-existing nuclei. The local activation energy is stable during the whole crystallization process and this further confirms that the crystallization occurs through a single mechanism. Ti20Zr20Cu20Ni20Be20 alloy can be classified into “strong glass formers” according to the estimated fragility index and also shows a relatively low value of Gibbs free energy difference. However, compared with Zr41.2Ti13.8Cu12.5Ni10Be22.5 BMG, the glass-forming ability of Ti20Zr20Cu20Ni20Be20 HE-BMG is much lower and the related reasons have been discussed.

A quinary Ti20Zr20Hf20Be20Cu20 high entropy bulk metallic glass (HE-BMG), with a critical diameter (Dc) of 12 mm—the largest size in the reported quinary high entropy alloys (HEAs), has been successfully prepared by copper mold casing. This novel HE-BMG possesses a supercooled liquid region ΔT (=Tx − Tg) of 78 K, indicating a better thermal stability than those of other HE-BMGs. In addition, the HE-BMG exhibits a relatively good compressive plasticity (2.2 ± 0.1%) among the HE-BMGs. The newly developed HE-BMG may offer insights for the indepth understanding of the fundamental issues associated with the glass formation and the unique structure-property relationship when combining the features of HEAs and BMGs together.

The non-isothermal crystallization kinetics and glass-forming ability of Ti41Zr25Be28Fe6 glassy alloy were investigated by differential scanning calorimetry. The activation energies corresponding to the characteristic temperatures have been calculated by Kissinger and Ozawa equations. Based on Kissinger–Akahira–Sunose and Ozawa–Flynn–Wall models, it has been found that the local activation energy is higher at the beginning of the crystallization process for the first exothermic peak. The local Avrami exponent indicates that the first-step crystallization is mainly a high-dimensional nucleation and growth with an increasing nucleation rate. According to the calculated fragility index, Ti41Zr25Be28Fe6 alloy can be classified as “strong glass former.” The studied alloy also possesses a critical size up to centimeter order, and the high glass-forming ability is probably related to the relatively low Gibbs energy difference between the liquid and crystalline states. The critical cooling rate of Ti41Zr25Be28Fe6 glassy alloy has also been determined using Barandiaran–Colmenero’s method.

Compared with Ti41Zr25Be28Fe6 bulk metallic glass, (Ti41Zr25Be28Fe6)93Cu7 glassy alloy possesses a much narrower supercooled liquid region but the glass-forming ability is dramatically improved. Isochronal and isothermal differential scanning calorimetry measurements were adopted to investigate Cu-alloying effect on the crystallization transformation kinetics of Ti41Zr25Be28Fe6 glassy alloy. It is found that Cu alloying increases the activation energies of Ti41Zr25Be28Fe6 glassy alloy for glass transition and crystallization in continuous heating. Moreover, the isothermal activation energy of (Ti41Zr25Be28Fe6)93Cu7 glassy alloy increases as process of crystallization transformation, while Cu-free alloy exhibits a contrary tendency. The addition of Cu also decreases the Avrami exponent of the base alloy, resulting in the suppression of crystal nucleation and growth.

Quantitative prediction of glass forming ability using a priori known parameters is highly desired in metallic glass development; however proven to be challenging because of the complexity of glass formation. Here, we estimate the number of potential metallic glasses (MGs) and bulk metallic glasses (BMGs) forming systems and alloys, from empirically determined alloy design rules based on a priori known parameters. Specifically, we take into account atomic size ratio, heat of mixing, and liquidus temperature, which we quantify on binary glasses and centimeter-sized BMGs. When expanding into higher order systems that can be formed among 32 practical elements, we reduce the composition space for BMG formation using developed criteria by 106 times and estimate ∼3 million binary, ternary, quaternary, and quinary BMGs alloys.

We used pulsed laser beam welding method to join Pd43Cu27Ni10P20 (at.%) bulk metallic glass and characterized the properties of the joint. Fusion zone and heat-affected zone in the weld joint can be maintained completely amorphous as confirmed by X-ray diffraction and differential scanning calorimetry. No visible defects were observed in the weld joint. Nanoindentation and bend tests were carried out to determine the mechanical properties of the weld joint. Fusion zone and heat-affected zone exhibit very similar elastic moduli and hardness when compared to the base material, and the weld joint shows high ductility in bending which is accomplished through the operation of multiple shear bands. Our results reveal that pulsed laser beam welding under appropriate processing parameters provides a practical viable method to join bulk metallic glasses.

Metallic core–shell nanostructures have inspired prominent research interests due to their better performances in catalytic, optical, electric, and magnetic applications as well as the less cost of noble metal than monometallic nanostructures, but limited by the complicated and expensive synthesis approaches. Development of one-pot and inexpensive method for metallic core–shell nanostructures’ synthesis is therefore of great significance. A novel Cu network supported nanoporous Ag-Cu alloy with an Ag shell and an Ag-Cu core was successfully synthesized by one-pot chemical dealloying of Zr-Cu-Ag-Al-O amorphous/crystalline composite, which provides a new way to prepare metallic core–shell nanostructures by a simple method. The prepared nanoporous Ag-Cu@Ag core-shell alloy demonstrates excellent air-stability at room temperature and enhanced oxidative stability even compared with other reported Cu@Ag core-shell micro-particles. In addition, the nanoporous Ag-Cu@Ag core-shell alloy also possesses robust antibacterial activity against E. Coli DH5α. The simple and low-cost synthesis method as well as the excellent oxidative stability promises the nanoporous Ag-Cu@Ag core-shell alloy potentially wide applications.

Deformation of metallic glasses is closely related to their microstructures which depend on the composition, processing method, and the size of the materials. This subtle structure-property relation is fairly complex and remains to be explored. Here, we scrutinize the microstructural evolution in relation to the mechanical properties in metallic glass nanowires with the same composition and size but subtle microstructural differences by controlling the preparing process using molecular dynamics simulations. The results suggest that a structural threshold exists for the transformation of deformation mechanisms in metallic glasses: when the structural feature exceeds the threshold, the deformation changes from homogeneous flow to shear localized deformation.