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Ultrafine Cu2O/CuO nanosheet arrays integrated with NPC/BMG composite rod for photocatalytic degradation
摘要： A free-standing Cu2O/CuO@nanoporous copper/bulk metallic glass (Cu2O/CuO@NPC/BMG) composite rod with a multimodal hierarchical porous structure has been successfully prepared by a facile two-step synthesis strategy consisting of dealloying and anodizing. The NPC/BMG composite is first fabricated by dealloying of Cu50Zr45Al5 BMG rod. Then the ultrafine Cu2O/CuO nanosheet arrays are synthesized by anodizing of the NPC/BMG rod followed by heat treatment. The as-obtained Cu2O/CuO@NPC/BMG composite possesses a multimodal hierarchical porous structure comprising interconnected pores ranging from micro, meso to macro sizes. It is worth pointing out that there are several “barren lands” without nanosheets grown on the surface of the composite. Further analyses indicate that the microstructures of substrate materials not only dominate the sizes of Cu2O/CuO sheets, but also influence the nucleation and growth of Cu2O/CuO sheets. Meanwhile, the possible formation mechanism of the Cu2O/CuO nanosheets is proposed. Accordingly, the Cu2O/CuO@NPC/BMG composite shows remarkably high photocatalytic degradation performance and excellent cycling stability for RhB due to the multimodal hierarchical porous structure, ultrafine Cu2O/CuO nanosheets in the entire NPC and the integration design strategy.
关键词： Metallic glass,Dealloying,Nanoporous,Anodizing,Nanosheet
更新于2025-11-14 17:03:37
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Nanosecond-pulsed laser welding of metallic glass
摘要： This study explores nanosecond-pulsed (ns-pulsed) laser welding on the metallic glass (MG) ribbons of four compositions: Fe78Si9B13, Zr65Cu15Ni10Al10, La55Ni20Al25 and Ce65Al10Cu20Co5. All MGs can be welded in the air by the ns-pulsed laser, and the crystallization of the welding joints can be avoided by proper control of the laser parameters. By varying the travel speed, pulse duration and repetition frequency, the critical crystallization time of MG can be quickly detected in a high-throughput way by ns-pulsed laser welding. At the optimal processing conditions, 70–90% of the tensile strength of the parent melt-spun ribbon can be preserved in the welded MG ribbons. The mechanical strength is well linked to the pro?le of the welding joint, which suggests a simple method to evaluate the welding quality. A welding parameter map has been established based on the experiments, and it is concluded that the laser power-density per sample thickness and the interaction time are the key factors that control the crystallization and strength of the welding joints. The map is valid for a broad range of MG compositions of all sample thickness, and thus the optimal processing conditions may be extended to all MGs with equivalent glass-forming ability.
关键词： Strength,Metallic glass,Thickness,Laser welding,Welding parameter map
更新于2025-09-23 15:19:57
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Development of process parameters for selective laser melting of a Zr-based bulk metallic glass
摘要： Parameters for selective laser melting of Zr59.3Cu28.8Al10.4Nb1.5 (trade name AMZ4), allowing crack-free bulk metallic glass with low porosity, have been developed. The phase formation was found to be strongly influenced by the heating power of the laser. X-ray amorphous samples were obtained with laser power at and below 75 W. The as-processed bulk metallic glass was found to devitrify by a two-stage crystallization process within which the presence of oxygen was concluded to play an essential role. At laser powers above 75 W, the observed crystallites were found to be a cubic phase (Cu2Zr4O). The hardness and Young’s modulus in the as-processed samples was found to increase marginally with increased fraction of the crystalline phase.
关键词： Selective Laser Melting,AMZ4,Bulk Metallic Glass
更新于2025-09-23 15:19:57
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Investigations in the fabrication of surface patterns for wettability modification on a Zr-based bulk metallic glass by nanosecond laser surface texturing
摘要： Laser texturing has previously been employed to enhance the wettability of metallic alloys. Such studies reported that modifying the wettability of a surface is a result of changes in both its topography and its chemistry. In this paper, an investigation about laser-induced surface wettability modification is also reported but for a less studied type of material in this context. In particular, nanosecond (ns) laser processing was employed to texture two types of surface patterns, i.e. dimples and grooves, on the surface of a Zr-based bulk metallic glass (BMG) known as Vitreloy 105. The specific focus of the research was on understanding the role played by both surface topography and chemistry modifications in changing the wettability of the original surface. Using static contact angle measurements, it was found that groove patterns enhanced the hydrophilicity of the original BMG, while dimple patterns weakened it. Based on the obtained 3D surface measurements and XPS data, it is suggested that the reduced hydrophilicity of dimple-textured surfaces was driven by the decrease of hydrophilic C=O and O=C-O bonds post laser processing. While these bonds were also reduced for groove-textured patterns, the hydrophilicity was still enhanced following laser irradiation as a result of the dominant role that a much larger induced surface roughness should play in this case.
关键词： Surface topography,Bulk metallic glass,Nanosecond laser surface texturing,Surface chemistry.,Wettability
更新于2025-09-23 15:19:57
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Effects of different annealing processes on optoelectronic and bending fatigue properties of AgZr and ITO/AgZr thin film metallic glass
摘要： Transparent conducting oxide (TCO) films are widely used throughout the optoelectronics industry. The present study explores the optoelectronic responses of AgZr (AZ) and ITO/AgZr (IAZ) thin film metallic glasses (TFMGs) with different Ag and Zr compositions and processed by two different annealing methods, namely furnace annealing (FA) and laser annealing (LA). Among the various as-deposited AZ and IAZ films, the ITO/Ag66Zr34 (IA6Z) film has the highest optical transmittance (55.7%) and the lowest sheet resistance (145.8 Ω/□). For the FA samples, an annealing temperature of 300 °C results in the optimal optoelectronic properties, namely a transmittance of 68.4% and a sheet resistance of 47.2 Ω/□. For the LA samples, the optimal processing conditions (a pulse energy of 2.5 μJ and a repetition rate of 150 kHz) yield optical transmittance and sheet resistance values of 64.0% and 17.8 Ω/□ respectively. The optimal LA processing conditions increase the Haacke figure of merit of the IA6Z sample from 2.0 × 10?5 under the as-deposited condition to 6.5 × 10?4 Ω?1 under the annealed condition; corresponding to a 32.5-fold improvement. Finally, the relative change in resistivity (ΔR/R0, where R0 is the initial resistivity, Ri is the measured resistivity after a certain number of cycles, and ΔR is Ri - R0) of the as-deposited IA6Z sample following fatigue testing (10,000 cycles) with a bend radius of 7 mm (ΔR/R0 = 0.49) is significantly lower than that of a pure ITO film of roughly equivalent thickness (ΔR/R0 = 0.93).
关键词： Laser annealing,Bi-layered electrode,Furnace annealing,Thin film metallic glass
更新于2025-09-19 17:15:36
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Relating fracture toughness to micro-pillar compression response for a laser powder bed additive manufactured bulk metallic glass
摘要： A Zr-based bulk metallic glass produced using selective laser melting (SLM) was compared to the same alloy fabricated using traditional suction-casting. Analysis of the fracture toughness and mechanism through single edge notched beam bending experiments show a significantly reduced damage tolerance for the laser-processed material (KQ ~ 138.0 ± 13.1 → 28.7 ± 3.7 MPa √m), even though X-ray diffraction and microhardness responses were identical. Uncovered here using uniaxial quasistatic micro-pillar compression, as-cast samples more readily undergo shear transformations (evidenced through discrete load drops) below the nominal 0.2% yield stress, which can be connected to the higher macroscopic toughness. Differential scanning calorimetry demonstrated that the increased barrier to shear transformation for the SLM material could not be explained by the relative relaxation states. Rather, it is attributed to the greater dissolved oxygen concentration in the laser-processed material, which is postulated to decrease atomic mobility in the structure and thereby increase the activation energy required to initiate shear transformations.
关键词： fracture toughness,metallic glass,amorphous materials,additive manufacturing,selective laser melting,micromechanics
更新于2025-09-19 17:13:59
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Reduced bacterial adhesion on zirconium-based bulk metallic glasses by femtosecond laser nanostructuring
摘要： As high-performing materials, bulk metallic glasses have attracted widespread attention for biomedical applications. Herein, the bacterial adhesion properties of femtosecond laser-nanostructured surfaces of four types of zirconium-based bulk metallic glasses are assessed. Laser-induced periodical surface structures and nanoparticle structures were fabricated by femtosecond laser irradiation under different energy intensities (0.23 and 2.3 J/mm2). Surface topography, roughness, wettability, and surface energy were investigated after femtosecond laser irradiation and the surface bacterial adhesion properties were explored using Escherichia coli and Staphylococcus aureus as respective representatives of Gram-negative and Gram-positive bacteria. 4#,6-Diamidino-2-phenylindole fluorescence staining was used to characterize and assess the bacterial surface coverage rate. The in vitro cytotoxicity of polished and laser-nanostructured surfaces was investigated using MC3T3-E cells. The obtained results demonstrate that femtosecond laser surface nanostructuring retained the amorphous structure of zirconium-based bulk metallic glasses and led to an obvious decrease in bacterial adhesion compared with polished surfaces. The inhibition of bacterial adhesion on laser-induced periodical surface structures was greater than on nanostructured surfaces after 24 h of bacterial incubation. In addition, femtosecond laser nanostructuring did not have an apparent effect on the cytotoxicity of zirconium-based bulk metallic glasses.
关键词： femtosecond laser,Bacterial adhesion,nanostructure,bulk metallic glass
更新于2025-09-16 10:30:52
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Surface resonance properties of pure Cu and Cu80Zr20 metallic glass films with nanoparticles induced by pulsed-laser dewetting process
摘要： Pure Cu and Cu80Zr20 thin films with a thickness of 10 nm were deposited on glass substrates using a high-vacuum sputtering system. A pulsed-laser dewetting process was then performed using a NIR laser system. For the pure Cu film, nanoparticles were produced for the accumulated energy (AE) densities in the range of 0.6~11 J/cm2. The particle size was found to increase with increasing scanning speed and repetition rate, and with decreasing power. For the Cu80Zr20 thin film, nanoparticles were formed under all AE values under consideration. The nanoparticles consisted almost entirely of Cu; with the Zr atoms being repelled to the bottom of the nanoparticle and surroundings. The optical absorption peak wavelengths for the Cu and Cu80Zr20 films produced under different dewetting conditions all lay in the range of 580~700 nm. Hence, it was inferred that the nanoparticles produced in the two films had a similar size, shape and composition.
关键词： surface resonance properties,Pulsed-laser dewetting,metallic glass,nanoparticle
更新于2025-09-12 10:27:22
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Femtosecond laser-induced non-centrosymmetric surface microstructures on bulk metallic glass for unidirectional droplet micro-displacement
摘要： Unidirectional droplet motion without energy input has attracted considerable attention in various potential applications. We report on the fabrication of unconventional laser-induced periodic surface structures (LIPSS) for unidirectional droplet micro-displacement by femtosecond laser at large incident angle. In order to overcome the mechanical durability of the existing soft materials such as PDMS for controlling the droplet, Zr-based bulk metallic glass (Zr-BMG) is used to fabricate the typical non-centrosymmetric unconventional LIPSS, which include micro-sized elliptical arc-shaped structures and nano-ripples with the central spatial periodicity of 400 nm. The spots and the grating of unconventional LIPSS on Zr-BMG are fabricated to construct the functional surface structures by femtosecond laser irradiation. The unidirectional micro-displacement of water droplet on Zr-BMG was achieved using functional surface structures. For better understanding the fabrication of unconventional LIPSS, the underlying formation mechanism was revealed by numerical simulations. This work gives a fast, precise and low-cost method to fabricate the non-centrosymmetric surface micro/nano-structures on metal materials for unidirectional droplet motion in microfluidics.
关键词： laser surface structuring,unidirectional droplet motion,LIPSS,bulk metallic glass,Ultrafast laser
更新于2025-09-11 14:15:04
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Mechanical properties of Zr-based bulk metallic glass parts fabricated by laser-foil-printing additive manufacturing
摘要： The application of bulk metallic glasses (BMGs) has been traditionally limited to parts with small dimensions and simple geometries, due to the requirement of fast cooling during the conventional process of casting. This research exemplifies a promising additive manufacturing method, i.e., laser-foil-printing (LFP), to fabricate high-quality BMG parts with large dimensions and complex geometries. In this study, Zr52.5Ti5Al10Ni14.6Cu17.9 BMG parts were fabricated by LFP technology in which MG foils are laser welded layer-by-layer upon a substrate. The mechanical properties of the fabricated BMG parts were measured using micro-indentation, tensile test and four-point bending test, and compared to as-cast BMG parts. Through LFP, as rapid cooling rates can be achieved, fully amorphous and nearly fully dense BMG parts without cracking have been successfully made. The glass transition temperature, crystallization temperature, and melting temperature of the fabricated parts are nearly the same as those of the as-cast parts. Additionally, the fabricated BMG parts exhibit mechanical properties, including micro-hardness, tensile strength, and flexural strength, comparable to the as-cast BMG parts.
关键词： laser processing,additive manufacturing,bulk metallic glass,mechanical properties
更新于2025-09-09 09:28:46