Ni-based Metallic Glass Research Articles

Optimizing Ni-Zr-Ti metallic glasses: Cluster design and molecular dynamics evaluation of glass forming ability

Ni-based metallic glasses have garnered significant attention due to their excellent mechanical properties and wide application prospects. However, their low glass forming ability (GFA) limits broader applications. This study explores the Ni-Zr-Ti ternary system, which excludes precious metals, using clusters and mixing entropy composition design method to develop a series of Ni-based metallic glasses with improved GFA. The study found that the composition Ni60.91Zr24.97Ti14.12 (NZT3) had the best GFA, with its cluster expression Ni-Ni8Ti4 + 1.17838 Ni-Ni6Zr6. To gain a deeper understanding of the GFA of metallic glasses, molecular dynamics (MD) simulations were conducted on the designed compositions. The simulation results indicated a significant correlation between the average local five-fold symmetry (ALFFS) and the GFA of the compositions. Ni60.91Zr24.97Ti14.12 exhibited the highest ALFFS value and the best GFA. The research demonstrates that by combining clusters and mixing entropy composition design method with the simulated ALFFS, metallic glasses with excellent GFA in the Ni-Zr-Ti system can be rapidly screened. The successful application of this innovative approach in this system not only deepens the understanding of metallic glass formation mechanisms but also provides significant guidance for future materials design.

Relief transformation of Ni-based metallic glass ribbon upon annealing in β-relaxation region

Relief transformation of Ni-based metallic glass ribbon upon annealing in β-relaxation region

Friction mechanisms of Ni-based and Zr-based bulk metallic glasses under different contact pressures

Pin-on-plane dry friction tests of Ni-based and Zr-based bulk metallic glasses were performed at ambient temperature under reciprocating sliding condition at 4 mm/s, under 160 MPa and 290 MPa. Domed 100Cr6 steel pins were used as counterface material. The friction performance of Ni-based glass is worse than the Zr-based glass but the former has a relatively more stable feature. For all metallic glasses, lower friction and more stable process can be observed upon higher contact pressure. Transfer of material from metallic glass samples onto steel pin surfaces is analyzed in details at the micrometer scale, showing that tribological properties of metallic glasses at high pressure could be related to the volume hardness of materials, together with the glass transition temperature.Keyworks:Metallic glasses, Third body flow, Wear, Friction performance

Differences in structure and dynamics of ternary Pd–Ni-based bulk metallic glasses containing sulfur or phosphorous

The composition Pd31Ni42S27 has been shown to be the best glass former in the family of recently discovered glass forming PdNiS alloys. In this study, this sample system was systematically investigated using fluctuation- and correlation electron microscopy of which the results are compared to a Pd40Ni40P20 bulk metallic glass that serves as a model system for metallic glasses. Strong differences in the local atomic correlations beyond the short-range order were observed, which are assumed to be a reason for their discrepancy in thermal stability. The relaxation dynamics at room temperature revealed faster dynamics in the sulfur-containing Pd31Ni42S27 glass.

Ductile Ni-based bulk metallic glasses at room temperature

In this work, a series of new Ni76-xCoxNb4P16B4 (x = 5, 10, 15, in at.%) bulk metallic glasses (BMGs) with the maximum diameter in the range of 1.2–1.6 mm were prepared by combining fluxing and J-quenching technology. The effects of Co content on glass forming ability (GFA), thermal stability, mechanical properties, serrated-flow behaviors and corrosion performance of the present Ni-based BMGs were systematically investigated. The ranges of Tg and ΔTx are 664–668 K and 21–31 K, respectively. Uniaxial compressive tests revealed that the present Ni-based BMGs have the compressive plastic strain (εp), yield strength (δy), and fracture strength (δf) that range from 16% to 27%, 2.1–2.6 GPa, and 2.2–3.6 GPa, respectively. The unprecedented mechanical properties originate from more icosahedral-like clusters (ILCs) and crystal-like clusters (CLCs) in the present Ni-based BMGs. It is found that the serrated-flow behaviors of the present Ni-based BMGs transition self-organized critical state (SOCs) into chaotic state (Cs) as plasticity decreases. The stick-slip dynamics were used to calculate the average shear-band velocity (ASBV), which shows an increasing trend as the Co content rises from 5 at.% to 15 at.%. Electrochemical measurements in 3.5 wt.% NaCl solution showed that the Ni71Co5Nb4P16B4 BMG has a self-corrosion current density of 3.30 × 10−8 A/cm2 and significantly stronger corrosion resistance than austenite 316L and 304L stainless steel. The present Ni-based BMGs have excellent comprehensive performance, which has great potential for industrial applications.

Increased ductility of Ni-based metallic glass ribbon pre-annealed at β-relaxation temperature

Increased ductility of Ni-based metallic glass ribbon pre-annealed at β-relaxation temperature

Laser-Based Additive Manufacturing and Characterization of an Open-Porous Ni-Based Metallic Glass Lattice Structure (Ni60Nb20Ta20).

Due to their amorphous structure, metallic glasses exhibit remarkable properties such as high strength, hardness, and elastic strain limit. Conversely, they also exhibit high susceptibility to brittle fracture, making them less qualified for the use as monolithic structural components. Therefore, they may be preferably used as the reinforcing phase in hybrid materials combined with ductile matrix materials. Especially metal matrix composites with interpenetrating structures are suitable. This requires an open-porous structure of the metallic glass. In the study at hand, an open-porous lattice structure was manufactured from metallic glass powder (Ni60Nb20Ta20) by laser powder bed fusion. A parameter study was carried out with various scanning strategies to manufacture a mechanically stable lattice structure while maintaining the amorphous structure of the metallic glass. Thus, X-ray diffraction measurements were conducted to validate the parameter study. A stable lattice structure with a largely amorphous structure was successfully achieved with a scanning strategy of single scanned lines and a rotation of 90° for each layer. However, nanocrystallization of 7% occurred in the heat-affected zones formed between the individual printed layers during reheating. Conducting compression tests, a compressive modulus of 18 GPa and a maximum strength of 90 MPa in 0°-direction were achieved. In 90°-direction, no compressive modulus could be determined but compressive strength resulted in 15 MPa. Performing nanoindentation with a Young's modulus of 195.1 GPa and Vickers hardness of HVIT = 956.1 was achieved for the printed bulk metallic glass alloy. The resulting lattice structure was further characterized by differential scanning calorimetry for thermal behavior.

Crystallization and thermal stability of Ni-based metallic glass with high tungsten and boron

Non-isothermal crystallization behavior of the amorphous (Ni51W31.6B17.4)75Co25 alloy with high tungsten and boron content was investigated. Continuous heating DSC analyses of the amorphous samples revealed that the alloy undergoes crystallization with three-step. The thermal stability and crystallization kinetics of the samples were evaluated by Lasocka, Kissinger and Ozawa approaches. Activation energy calculated for the first crystallization step showed that the thermal stability of the NiCoWB alloy is higher than other Ni-based alloys. Avrami exponent value calculated for the early stage of the Niss-phase crystallization indicated a three-dimensional diffusion-controlled mechanism with increasing nucleation. The continuous heating transformation diagram plotted according to non-isothermal analyzes is consistent with the phases detected in isothermal heat treatments. The usability of the continuous heating transformation diagram of the alloy in isothermal heat treatment applications has been demonstrated.

Strength of 444 Stainless Steel Single-Lap Joints Brazed with Ni-Based Metallic Glass Foils for Corrosive Environments

Strength of 444 Stainless Steel Single-Lap Joints Brazed with Ni-Based Metallic Glass Foils for Corrosive Environments

Strength of 316L Stainless Steel Single-Lap Joints Brazed with Ni-Based Metallic Glass Foils for Corrosive Environments

In brazing, the choice of base metal, brazing filler metal (BFM), and braze process conditions involves complex tradeoffs among cost, mechanical strength, corrosion resistance, and others. In this work, the tradeoff between strength and corrosion resistance of 316L stainless steel joints brazed with a newer “very corrosion-resistant” Ni-Cr-P-Mo-Si BFM and a more established “corrosion-resistant” Ni-Cr-Si-B BFM is quantitatively analyzed. Corrosion tests and microstructural analyses were performed using common practices. Joint strength was evaluated by testing brazed single-lap joints (SLJs) in tension following standardized procedures. However, conventional interpretations were found to be inadequate for quantitative comparisons. Therefore, the SLJ stress state was analyzed in detail and a complete interpretation was developed. Joint strength is shown to be determined by the SLJ geometry, base metal properties, and braze microstructure. This analysis was used to explain the occurrence of different failure modes (fast fracture, peeling, and base metal failure) and to make suggestions for improved methods for conducting and analyzing brazed SLJ tensile tests. The newer BFM is shown to provide significantly better corrosion resistance for a moderate reduction in mechanical strength.

Thermoplastic brazing of TiAl- and Ni-based alloys utilizing a Ni-based bulk metallic glass as the filler metal

Good high-temperature property is of great significance for TiAl/Ni joint. In this work, a (Ni60Nb15Zr15Ti10)98Co2 BMG was designed and applied as the filler metal to join TiAl- and Ni-based superalloy utilizing TPB method. Good physical prebonding was firstly achieved at temperatures much lower than the melting point by superplastic filling of the BMG and metallurgical bonding was then realized through solid-state atomic diffusion at higher temperatures. Superplastic filling and crystallization behaviors of the BMG in the superliquid region were analyzed and the experimental results indicated that after superplastic deformation in the superliquid region, no crystallization occurred and a compact contacting between base metals and filler metal was achieved. Temperature plays an important role in microstructure evolution of the joint. With increasing the diffusion temperature, the reaction layer between the Ni-based alloy and BMG become thicker. Small isotropic phases derived from crystallization of the amorphous with the dimension ranging from nanoscale to several micro of the joint were formed in the joint after bonding. Focused Ion beam (FIB), transition electron microscope (TEM) and selected area electro diffraction (SAED) were applied to further determine the small isotropic phases. Shearing tests performed at room temperature and 1023K were used to examine the strength of the joint and the results showed that the shear strength at room temperature and at 1023K were as high as 365 MPa and 260 MPa.

Improving glass forming ability of off-eutectic metallic glass formers by manipulating primary crystallization reactions

Glass forming ability (GFA) is critically important for large-scale applications of bulk metallic glasses with maximized functionalities at low costs in materials and processing. Traditionally, excellent glass formers usually have compositions in eutectic regions where liquid phases have high stability and low liquid temperatures while GFA of off-eutectic alloys is largely limited by primary crystallization. In this study we reported that the GFA of Ni-based off-eutectic alloys can be dramatically improved by manipulating the primary crystallization reaction through minor alloying. As a result, a novel Ni60Pd20P14Si2B4 metallic glass with excellent GFA is developed by substituting P in Ni60Pd20P20 using 2 at.% Si and 4 at.% B. The minor alloying leads to the transition of the primary crystallization from a tetragonal (Ni, Pd)3P phase to a chemically modulated complex monoclinic phase. The enhanced GFA results in the largest achievable processing diameter (25 mm) of Ni-based bulk metallic glasses, which is more than four times larger than that of Ni60Pd20P20. The complex crystal structure of the primary crystalline phase with chemical modulation and a large unit cell leads to slow crystal growth, and hence the improved stability of supercooled liquid for better GFA.

Surface-governed electrochemical hydrogenation in FeNi-based metallic glass

The hydrogenation and oxide formation behavior of Fe–Ni-based metallic glasses (MGs), where measurements by the conventional gas-solid reaction method are difficult, is analyzed by a two-step approach: chronoamperometry followed by cyclic voltammetry (CA + CV). We introduce a concept of effective volume by measuring the thickness of the region where the hydrogen and hydroxyl ion interactions with Fe-based MG take place, which is characterized by high-angle annular dark-field scanning transmission electron microscopy. A very constant film thickness influenced by the OH− and H+ is confirmed by TEM, where the chemical homogeneity is maintained within this region. The weight percent of hydrogen and the corresponding hydrogen-to-metal ratio are determined as 1.16% and 0.56, respectively. When compared to previous studies conducted by the electrochemical-permeation method, the H/M ratio is found to be an order of magnitude larger. Electrochemical impedance spectroscopy (EIS) and subsequent equivalent circuit modeling (ECM) of the tested ribbons resolve the surface-diffusion processes for hydride formation and oxidation kinetics. This contribution provides a different perspective for the design and study of low-cost and high-performance amorphous nanofilms for hydrogen-energy applications, particularly when the common gas-adsorption methods are problematic.

Improving Glass Forming Ability of Off-Eutectic Metallic Glass Formers by Manipulating Primary Crystallization Reactions

Glass forming ability (GFA) is critically important for large-scale applications of bulk metallic glasses with maximized functionalities at low costs in materials and processing. Traditionally, excellent glass formers usually have compositions in eutectic regions where liquid phases have high stability and low liquid temperatures while GFA of off-eutectic alloys is largely limited by primary crystallization. In this study we reported that the GFA of Ni-based off-eutectic alloys can be dramatically improved by manipulating the primary crystallization reaction through minor alloying. As a result, a novel Ni60Pd20P14Si2B4 metallic glass with excellent GFA is developed by substituting P in Ni60Pd20P14Si2B4 using 2 at.% Si and 4 at.% B. The minor alloying leads to the transition of the primary crystallization from a tetragonal (Ni, Pd)3P phase to a chemically modulated complex monoclinic phase. The enhanced GFA results in the largest achievable processing diameter (25 mm) of Ni-based bulk metallic glasses, which is more than four times larger than that of Ni60Pd20P14Si2B4 . The complex crystal structure of the primary crystalline phase with chemical modulation and a large unit cell leads to slow crystallization kinetics from high barrier energy for crystal nucleation and growth, and hence the improved glass forming ability.

Experiments on the Ultrasonic Bonding Additive Manufacturing of Metallic Glass and Crystalline Metal Composite.

Ultrasonic vibrations were applied to weld Ni-based metallic glass ribbons with Al and Cu ribbons to manufacture high-performance metallic glass and crystalline metal composites with accumulating formation characteristics. The effects of ultrasonic vibration energy on the interfaces of the composite samples were studied. The ultrasonic vibrations enabled solid-state bonding of metallic glass and crystalline metals. No intermetallic compound formed at the interfaces, and the metallic glass did not crystallize. The hardness and modulus of the composites were between the respective values of the metallic glass and the crystalline metals. The ultrasonic bonding additive manufacturing can combine the properties of metallic glass and crystalline metals and broaden the application fields of metallic materials.

A novel Ni-based bulk metallic glass containing high amount of tungsten and boron

Glass forming ability (GFA) and thermal stability of (Ni51W31.6B17.4)100-xCox (x = 0–35) alloy system have been investigated. It is found that as the cobalt content is increased critical casting thicknesses improve significantly. Critical casting thickness of 20, 25 and 30 at. % cobalt alloys are determined as 0.5, 1, and 1 mm, respectively. However, further increase of cobalt content degrades the GFA. The Ni-based bulk metallic glasses discovered in this study are the first ones ever developed which contain more than 10 at. % boron. It is also determined that after annealing the fully amorphous samples above their first and second crystallization temperatures, nickel solid solution and CoWB phase precipitate. This is the first study where precipitation of ultra-hard CoWB phase in a bulk metallic glass is reported.

Wire electrochemical micromachining of Ni-based metallic glass using bipolar nanosecond pulses

The up-and-coming trend of product miniaturization alongwith application of novel materials with extreme properties has created a challenge for machining industry. Newly developed wire electrochemical micromachining (WECMM), as an important nontraditional micromachining technique, has been identified as a promising method for fabrication of microcomponents on a wide range of conductive materials. However, in many cases, the processing performance is typically limited by the properties of tool cathode and the mass transport rate in the interelectrode, which plays a crucial role in further development of this technique. Herein, the use of bipolar nanosecond pulses is innovatively proposed to help reduce the deposition of electrolysis products on the tool electrode and the underlying mechanism is systematically analyzed. Helical carbon nanotube fiber (CNF) was used as a new tool cathode in vibration-assisted WECMM to enhance the mass transport rate. The microshaping characteristics of the proposed method using bipolar nanosecond pulses were then investigated using a Ni-based metallic glass that exhibits typical passivation behavior in dilute acidic electrolytes as a representative example. Compared with traditional unipolar pulses, the use of bipolar pulses could effectively inhibit passive film growth on the machining surface of metallic glasses. In addition, no tool wear occurred for CNF that the original surface morphology became rougher only at excessive negative voltages. Finally, functional microcomponents were successfully fabricated with overall improved processing performance.

A Ni(OH)2 nanopetals network for high-performance supercapacitors synthesized by immersing Ni nanofoam in water.

Developing a facile and environmentally friendly approach to the synthesis of nanostructured Ni(OH)2 electrodes for high-performance supercapacitor applications is a great challenge. In this work, we report an extremely simple route to prepare a Ni(OH)2 nanopetals network by immersing Ni nanofoam in water. A binder-free composite electrode, consisting of Ni(OH)2 nanopetals network, Ni nanofoam interlayer and Ni-based metallic glass matrix (Ni(OH)2/Ni-NF/MG) with sandwich structure and good flexibility, was designed and finally achieved. Microstructure and morphology of the Ni(OH)2 nanopetals were characterized. It is found that the Ni(OH)2 nanopetals interweave with each other and grow vertically on the surface of Ni nanofoam to form an “ion reservoir”, which facilitates the ion diffusion in the electrode reaction. Electrochemical measurements show that the Ni(OH)2/Ni-NF/MG electrode, after immersion in water for seven days, reveals a high volumetric capacitance of 966.4 F/cm3 at a current density of 0.5 A/cm3. The electrode immersed for five days exhibits an excellent cycling stability (83.7% of the initial capacity after 3000 cycles at a current density of 1 A/cm3). Furthermore, symmetric supercapacitor (SC) devices were assembled using ribbons immersed for seven days and showed a maximum volumetric energy density of ca. 32.7 mWh/cm3 at a power density of 0.8 W/cm3, and of 13.7 mWh/cm3 when the power density was increased to 2 W/cm3. The fully charged SC devices could light up a red LED. The work provides a new idea for the synthesis of nanostructured Ni(OH)2 by a simple approach and ultra-low cost, which largely extends the prospect of commercial application in flexible or wearable devices.

Ultrasonic additive manufacturing of bulk Ni-based metallic glass

It is difficult to produce bulk blanks directly from metallic glass, which limits its application. Ni-based metallic-glass thin strips that can be manufactured easily were used to manufacture bulk metallic glass additively by ultrasonic bonding. The effects of ultrasonic vibration energy on the quality of the additive manufacturing of bulk Ni-based metallic glass were studied. The experimental results showed that a fully amorphous structure of bulk Ni-based metallic glass can be obtained with an appropriate ultrasonic vibration energy. The thermal properties were almost unchanged, and the hardness and elastic modulus of the Ni-based metallic glass were improved compared with the original material. Additive manufacturing of bulk metallic glass by ultrasonic bonding can broaden the application field of metallic glass.

Ni-Based Metallic Glass Composites Containing Cu-Rich Crystalline Nanospheres

In this work, a quaternary Ni–Cu–Nb–Ta system has been designed to obtain composite microstructure with spherical crystalline Cu-rich particles embedded in amorphous Ni-rich matrix. The alloy samples were prepared by using single-roller melting-spinning method. The microstructure and thermal properties of the as-quenched alloy samples were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and differential scanning calorimetry. It shows that the spherical crystalline Cu-rich particles are embedded in the amorphous Ni-rich matrix. The average size of the Cu-rich particles is strongly dependent upon the Cu content. The effect of the alloy composition on the behavior of liquid–liquid phase separation and microstructure evolution was discussed. The phase formation in the Ni-based metallic glass matrix composite was analyzed.