Amorphous Alloy Material Research Articles

Achieving improved compression plasticity/strength in plasma sprayed Al2O3–GAP amorphous ceramic coatings by regulating spray powder phase compositions

In this work, Al2O3–GdAlO3 (GAP) amorphous ceramic coatings were prepared via plasma spraying. A novel method of regulating spray powder phase compositions was provided to obtain the different amorphous phase contents in Al2O3–GAP coatings. The α-Al2O3/c-Gd2O3 and α-Al2O3/GAP sprayable powders were individually applied to deposit the coatings, namely Coating 1# and Coating 2#. Their amorphous phase contents were 91.8 wt% and 55.4 wt%, respectively. X-ray diffraction, scanning electron microscope, electron backscattered diffraction, X-computed tomography, atom probe tomography and micropillar compression tests combined with finite element method were applied to analyze microstructural features and mechanical performance of the coatings. The results showed that Coating 2# possessed higher compressive strength (3.42 GPa) and greater compression plasticity (21.8 %) than Coating 1#. Compared with nearly 40 amorphous materials, Coating 2# had an excellent compression plasticity, which was better than almost all amorphous alloy materials, showing extremely attractive engineering application potential.

Alloying-Induced Synthesis of Amorphous PdZnS Hollow Spheres as Enhanced Oxygen Reduction Catalysts.

Amorphous alloys have multiple advantages in electrocatalysis, yet the isotropic nature makes their syntheses a great obstacle in application. In this work, it is shown that the Zn2+ can interfere with the crystallization of Pd-base structures to form amorphous alloy materials. By simply adjusting the Zn2+ content, unique PdZnS amorphous hollow spheres (AHS) with various compositions and degrees of crystallinity can be obtained through a facile one-pot wet chemical method. Owing to both the amorphous nature and hollow morphologies, the PdZnS AHSs possess appealing activities and stabilities as oxygen reduction catalysts. Typically, the Pd20 ZnS10 AHSs exhibit the highest half-wave potential (E1/2 ) of 0.940V (vs reversible hydrogen electrode), and such E1/2 only negatively shifts 25mV after 60000 cycles.

Scaling Law for Impact Resistance of Amorphous Alloys Connecting Atomistic Molecular Dynamics with Macroscale Experiments.

Establishing scaling laws for amorphous alloys is of critical importance for describing their mechanical behavior at different size scales. In this paper, taking Ni2Ta amorphous metallic alloy as a prototype materials system, we derive the scaling law of impact resistance for amorphous alloys. We use laser-induced supersonic micro-ballistic impact experiments to measure for the first time the size-dependent impact response of amorphous alloys. We also report the results of molecular dynamics (MD) simulations for the same system but at much smaller scales. Comparing these results, we determined a law for scaling both length and time scales based on dimensional analysis. It connects the time and length scales of the experimental results on the impact resistance of amorphous alloys to that of the MD simulations, providing a method for bridging the gap in comparing the dynamic behavior of amorphous alloys at various scales and a guideline for the fabrication of new amorphous alloy materials with extraordinary impact resistance.

Electromagnetic alternators with composite amorphous alloy shell for improving characteristics

In this study, a magnetic casing encapsulating a generator is used to improve the electromagnetic and power characteristics of the generator. Two types of two-pole AC generators are proposed: one is a bare-bonded (NC) type and the other is an iron-based amorphous alloy material covering the generator casing. In this study, Fe-Si-B amorphous thin strips were annealed between 300 and 380 °C and soaked for 60 min to observe and analyze the structural changes and the evolution of properties under different temperature conditions. After the thin strip is annealed at 400 °C, α-Fe dendrites begin to appear, and at 450 °C, a large number of α-Fe dendrites are formed. The demagnetization rate of the permanent magnet area near the bottom of the pole piece is the highest for the generator with an amorphous alloy shell because the magnetic flux leakage from the side frame of the pole piece changes the magnetic flux path, thereby affecting the demagnetization performance. In this study, three amorphous alloys, HB1-M, HB1, and SA1, were used as the cladding permanent magnet generator shell, and annealing and non-annealing procedures were conducted to observe the influence on the magnetic power of the generator. The magnetic flux on the surface of the amorphous shell was measured by a magnetic fluxmeter. For experiments with an amorphous shell, the results show that the annealed center point magnetic flux densities were approximately HB1-M (15 mT), HB1 (12 mT), and SA1 (10 mT), and the marginal non-annealed amorphous thin strip could reach ∼7–5 mT. The measured generator harmonic component of SA1 is higher than the voltage and current harmonics, reflecting that the magnetization direction of the magnetic shell in the demagnetization region is covered by the magnetic flux density. Because of central flame annealing, the magnetic shell is paramagnetic, and it helps to reduce the noise by at least 5 dB. The generator current harmonic characteristic of the HB1-M material is smaller than that of the HB1 and SA1 materials. In this study, a composite amorphous material was used to cover the generator casing; it was verified that HB1-M + HB1 + SA1 has the lowest noise characteristics for the generator. The generator noise of the composited material (HB1-M + HB1 + SA1) can be reduced to below 69 dB, which is ∼7–9 dB lower than that of a single amorphous material.

Nanocutting mechanisms of Cu50Zr50 amorphous alloy: A molecular dynamics simulation

Amorphous structures can achieve high mechanical strength and toughness, excellent magnetic properties, anti-corrosion, and anti-friction properties, resulting in their wide applicability, thereby prompting research interest in the role of nanofabrication for amorphous alloys. In this study, the deformation behavior of amorphous alloy Cu50Zr50 during nano cutting was investigated via molecular dynamics simulations. By analyzing the variations of the displacement vector, shear strain, cutting force, and cutting temperature, the removal mechanism of the amorphous alloy material was studied in detail. The amorphous alloy was removed via extrusion during nano cutting. The shear transition zone was formed via the local atomic superposition to form a shear band, and the atoms recovered elastically to form a machined surface. The effects of the cutting depth, cutting speed, and tool angle on the deformation behavior of the material were investigated. The results indicate that the cutting force, cutting temperature, and friction coefficient are increased with an increasing in cutting depth. An appropriate increase in the clearance angle and decrease in the rake angle can reduce the cutting force and friction coefficient. Based on the evolution law of the surface, the plastic transformation of the cutting amorphous alloys was predicted. At the cutting speed of 100–200 m/s, the friction coefficient remained unchanged, which accelerated the formation of a plastic transition zone. For different machining angles, the largest cutting force and surface roughness were obtained at 45°, whereas the least values were obtained at 60°. Therefore, the different machining angle can reduce the cutting forces and improve the quality of the machined surface.

Better utilization of materials’ compositions for predicting their properties: Material composition visualization network

Owing to the complexity and diversity of advanced high-performance materials, it is challenging to comprehensively understand a material’s composition–process–structure–performance relationship. Data-driven approaches have been regarded as the fourth paradigm of new materials R&D. However, the complexity of constituent elements in many material datasets leads to very sparse compositional features, posing a tremendous challenge to machine learning models. In this study, a data mapping scheme based on fundamental atomic features was used to visualize the chemical composition characteristics mapped into two-dimensional grayscale image data to solve the problem of sparse material composition matrix. Based on this, a material composition visualization network (MCVN) is proposed and applied to predict the mechanical properties of steel and classify amorphous alloy materials. We compared the MCVN to other machine learning methods. The MCVN had an average R2 value improvement of 4% on the four targets in the National Institute for Materials Science’s (NIMS’s) steel dataset, where other models already get an average R2 of 0.92, and it achieved an R2 of 0.835 on the cross-sectional shrinkage target in the Shanghai Research Institute of Materials’(SRIM’s) steel dataset where the other models only had an average R2 of 0.64. For the unbalanced amorphous alloy material dataset, the MCVN improved the average Recall of the small-class crystalline alloy (CRA) from 0.58 to 0.78. The method based on expanding the material chemical composition information is universal and provides a new paradigm for material property prediction.

Study of a High-Power Medium Frequency Transformer Using Amorphous Magnetic Material

A shell-type medium frequency transformer (MFT) using amorphous alloy material is designed for high-power electronic applications. The optimal area product design method is adopted to design an MFT, which maximizes the high efficiency and power density, minimizes the loss and volume, and meets the limitations of insulation and temperature rise. Then, a 20 kVA/10 kHz MFT is designed. To ensure the rationality of the MFT design, the magnetic properties of the amorphous alloy material are measured, and finite element simulations are carried out based on measured magnetic properties. The magnetic flux density, loss, and temperature rise of the designed MFT are analyzed. Finally, a 20 kVA/10 kHz MFT prototype is fabricated, and experimental tests are carried out. The loss and temperature rise of the MFT prototype are within reason, which verifies the effectiveness of the proposed scheme.

Experimental Investigation of Zr‐Based Amorphous Alloy as a Shaped Charge Liner

AbstractThis study aimed to investigate the mechanical properties of Zr‐based amorphous alloy at high strain rates and its use as a shaped charge liner. A split Hopkinson pressure bar (SHPB) was used to carry out dynamic mechanical performance tests, and a scanning electron microscope (SEM) was used to observe the fracture morphology of the test piece. The X‐ray test of the jet formation and the static penetration test of the Zr‐based amorphous alloy jet were performed. It was found that the amorphous alloy material exhibits typical brittle fracture characteristics under high strain‐rate compression. As the strain rate increases, molten droplet‐like structures appear in the fracture morphology, and the melting area is proportional to the strain rate. The Zr‐based amorphous alloy liner forms a non‐cohesive jet driven by explosive explosion. The actual projection angle of the liner is slightly larger than the theoretical value of Taylor's projection angle because of the unique mechanical properties and fracture mechanism, while the collapse angle is slightly smaller. Compared with copper jet penetrating concrete, the aperture of Zr‐based amorphous alloy jet is increased by 58 % and the caving volume is increased by 32 times. The results provide reference for the application of Zr‐based amorphous alloy in the field of shaped charge liner.

Design and Analysis of New Modular Stator Hybrid Excitation Synchronous Motor

Hybrid excitation motor is a combination of permanent magnet motor and electric excitation motor, which can flexibly adjust the air gap magnetic field. At present, the traditional silicon steel sheet core material is widely used, but this material limits the further reduction of stator iron loss. In this paper, a new type of hybrid excitation synchronous motor with modular stator structure based on amorphous alloy material is proposed. The design power is 1kW, and the speed is 3000rpm. By placing the armature winding and electric excitation winding in the stator slot, the slip ring and brush are avoided, and the reliability of the motor is improved. The rotor adopts staggered magnetic pole structure, which has strong flux adjusting ability. The core loss is greatly reduced by using amorphous alloy. Firstly, the structure and working principle of the new motor are given; Secondly, the size parameters of the motor are given, and the principle of flux adjustment is verified and analyzed by three-dimensional finite element(3D-FEM); Finally, through theoretical analysis of the influence factors of the magnetic adjustment ability and 3D-FEM finite element computation, the flux adjustment ability and the torque lifting at low speed are verified, and the advantages of the motor are verified.

Measurement Analysis and Improvement of Vibroacoustic Characteristics of Amorphous Alloy Transformer

The amorphous alloy transformer has a smaller coercive force and lower specific iron loss. It precedes the conventional silicon steel sheet transformer from the perspective of energy conservation. However, amorphous alloy material has a more significant magnetostriction coefficient, resulting in stronger vibration and acoustic noise. This paper investigates the measurement, analysis, and improvement of vibroacoustic characteristics of one three-phase, four-frame amorphous alloy distribution transformer to reduce environment noise pollution. This study adopts a coupling analysis method of magnetic–force–acoustic multi-physical fields to analyze the vibroacoustic characteristics. It then introduces a novel combination method of magnetic field analysis and an electric circuit to improve the efficiency of magnetic field analysis. This new combination method can greatly reduce the solution time of multiple physical fields through comparison with the traditional field-circuit coupling method. Different from other studies, this paper studies the acoustic and vibration characteristics of an amorphous alloy transformer under both no-load and load conditions. It is found that the load vibration noise of an amorphous transformer is more severe than that of a traditional silicon steel transformer. Accordingly, the study measures the vibroacoustic characteristic with different excitations and load levels under different working conditions to verify the numerical analysis method. Furthermore, according to the analysis results, this paper suggests a few vibration and noise control strategies. In conclusion, the paper deduces an essential basis for exploring strategies of vibration reduction and noise control for amorphous alloy distribution transformers.

The forming and crystallization behaviors of Zr50Ti5Cu27Ni10Al8 bulk amorphous alloy by laser additive manufacturing

Due to the small size and serious crystallization, the wider application of amorphous alloy materials is limited. In this paper, the bulk amorphous alloy with the size of 15 mm × 15 mm × 12 mm was made by selective laser melting technology. The characters of the composition and structure of the as-prepared bulk amorphous alloy and the thermal effect of the preparation process were analyzed. The results showed that the cooling rate of both the molten pool and the heat affected zone were much higher than the critical cooling rate of the amorphous alloy and, therefore, the cooling rate was not the reason for the crystallization in this experiment. The molten pool of the formed amorphous alloy block was completely amorphous. Due to the accumulation of structural relaxation, crystallization occurred in the heat affected zone, but the amorphous structure was still dominant. The increase in deposition layer had no obvious effect on crystallization.

Effect of Cutting and Slot Opening on Amorphous Alloy Core for High-Speed Switched Reluctance Motor

The amorphous alloy material has the characteristics of high resistivity and low loss, but the loss characteristic of the amorphous alloy core is unstable, which can be greatly affected by the processing. Thus, the calculation error of the amorphous alloy core loss turns out to be large, which leads to the difficulty in the design and optimization of the core. In this article, a new loss factor correction model of the amorphous alloy core is proposed to analyze the influence of the processing and core size on the loss. To verify the loss factor correction model, the loss characteristic of amorphous alloy material was tested and analyzed, and the core loss at different core sizes was compared. In addition, a mathematical model of core loss is proposed for the amorphous alloy stator core to optimize and calculate the loss of amorphous stator core. The correctness of the proposed model is verified by the test of core loss.

In vitro corrosion resistance and cytocompatibility of Mg66Zn28Ca6 amorphous alloy materials coated with a double-layered nHA and PCL/nHA coating

In this study, the double-layered nHA and PCL/nHA coatings were prepared on the substrate of Mg66Zn28Ca6 amorphous alloy. The phase composition and morphological were analyzed by Scanning electron microscopy, Energy dispersive spectrometry and X-ray diffraction. The electrochemical properties of these samples were measured on electrochemical workstation. The degradation rate was evaluated by measuring the pH value and weight loss. Experiment results show that the outer composite PCL/nHA coating is a porous structure, where the porosity and pore size could be easily controlled by adding nHA. The combined properties of double-layered nHA and PCL/nHA coating can control the degradation of the Mg66Zn28Ca6 amorphous alloy in the scheduled time. Moreover,the cell co-culture and cell adhesion tests show that the double-layered nHA and PCL/2%nHA coating possesses the best cytocompatibility with cell organization. The above experiments have demonstrated that the Mg66Zn28Ca6 amorphous alloy which was coated with PCL/nHA composite coating have good mechanical properties, good corrosion resistance and perfect cytocompatibility. It can be used as a potential novel biomaterial for bone tissue engineering.

A study on preparation and mechanism of Ni based ternary alloy

In this paper, the preparation of Ni–Ti–Nb amorphous alloy materials made by mechanical alloying method has been studied. The Ni–Ti–Nb mixed powders obtained by different mechanical alloying times have been analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the Ni–Ti–Nb mixed powders can be mechanically alloyed after milling for 10 hours, and retained with ball milling. Continuously, Ni, Ti and Nb alloy powders diffuse with each other. When the diffusion rate increases to a certain extent, it is too late to form an ordered structure and form a Ni–Ti–Nb amorphous alloy. The stress and displacement curves are obtained by testing the tensile strength at room temperature. The stress changes of the restrained curves are relatively stable when the displacement is 6–18 mm, and the stress changes of the unconstrained curves show a distinct upward trend when the displacement is 6–18 mm, indicating that the strength of the specimens treated with restraint is higher than that of the specimens treated with restraint. This is due to the high internal stress of the material caused by the restraint and the decrease in the tensile strength of the alloy material.

Investigation on Cutting Forces and Surface Finish in Mechanical Micro Milling of Zr-Based Bulk Metallic Glass

Precision micro-component fabrication demands suitable manufacturing processes that ensure making of parts with good form and finish. Mechanical micro milling represents a flexible and powerful process that exhibits enhanced capability to create micro features. Bulk metallic glass (BMG) represents a young class of amorphous alloy material with superior mechanical and physical properties and finds appreciable micro scale applications like biomedical devices and implants, micro parts for sport items and various other micro- components. In the present work, an attempt has been made to analyze the influence of the cutting parameters like spindle speed, feed per tooth and axial depth of cut on the machinability of BMG, in mechanical micro-milling process. The micro-milling process performances have been evaluated concerning to cutting forces and surface roughness generated, by making full slots on the workpiece with solid carbide end mill cutters. The paper presents micro-machining results for bulk metallic glass machined with commercial micro-milling tool at low cutting velocity regime. Response surface methodology (RSM) has been employed for process modeling and subsequent analysis to study the influence of the combination of cutting parameters on responses within the selected domain of cutting parameters. It has been found that the effect of axial depth of cut on the cutting force components is remarkably significant. Cutting force components increases with the increase in axial depth of cut and decreases with increase in spindle speed. At low feed rate, cutting force in the feed direction (Fx, i.e., cutting force along x-direction) increases with a decrease in feed rate. This increase of force could be due to the possible ploughing effect. A similar pattern of variation has been observed with cutting force component in cross-feed direction (Fy) also. It has been found that effect of feed per tooth on the roughness parameter Ra is remarkably significant. Surface roughness increases with feed per tooth. Axial depth of cut does not contribute much to the surface roughness. Surface roughness decrease with the increase of spindle speed.

Iron loss research of amorphous alloy motor by considering the influences of solidifying and annealing on stator core

PurposeThe specific iron losses of amorphous alloy material are extremely low compared with silicon steel material. The iron losses of motors may reduce by replacing the silicon steel core with an amorphous alloy core. However, one drawback of amorphous alloy material is that the specific iron losses will increase a lot after the motor manufacturing process. This paper aims to study the influences of interlaminar insulator solidifying and annealing on amorphous alloy material. The iron losses of motors made of amorphous alloy and baseline silicon steel sheets are compared and discussed.Design/methodology/approachThis paper opted for an exploratory study using the experimental analysis and loss separation methods. Two amorphous alloy cores are produced and tested. The iron losses of motors made of amorphous alloy and silicon steel sheets are calculated and compared based on the measured specific iron losses. Three wound amorphous alloy core samples are made and measured. The iron losses are separated and compared by considering the manufacturing influences.FindingsThis paper provides empirical insights about what change is brought in amorphous alloy material after manufacturing. The results have shown that, for amorphous alloy cores without the annealing process, the loss increase caused by solidifying is mainly the eddy current loss, while it is mainly the hysteresis loss component for annealed amorphous alloy cores.Originality/valueThis paper presents for the first time the measured results of manufactured amorphous alloy cores. This paper fulfils the need to manufacture amorphous alloy motors properly for the producers.

Study on Performances of Amorphous Three-Phase Asynchronous Motor

The motor of traditional silicon material possesses the disadvantages of high iron loss, power consumption and a low efficiency. A new type of motor iron core made of amorphous alloy material is put forward in this paper. First, in order to research the stator characteristics of amorphous iron core and silicon steel core, the stator core of three-phase asynchronous motor is fabricated with silicon and amorphous materials. The magnetic performances and alternating loss of the iron cores made by two kinds of materials are tested with in the TD8120 test system. Then, the finite element analysis model of three-phase asynchronous motor is established. The motor of amorphous iron core and silicon steel core are simulated by finite element method. It is showed that the simulation and test results are in good condition within error range. It can be known that the performance and efficiency of motor made by amorphous alloy core are better than the performance and efficiency of motor made by silicon steel core. Results presented in this paper have important significance to carry out the study of amorphous motor.

The Application of the Amorphous Metal Transformers in Heavy Oil Electric Heating System

In order to solve the problem that the big loss of no-load and the fast rise of temperature when employ the conventional silicon steel metal transformer (SSMT) in the electric heating system, we choose the amorphous metal transformer (AMMT). In this paper, firstly, we give a brief introduction of the amorphous alloy material properties and compare the no-load characteristic of the AMMT with the SSMT. Secondly, the structure of intermediate frequency heating system working principle and control strategy are introduced. Finally, extensive experiments were conducted to validate the ideas. The experiments show that the AMMT not only improve the efficiency of transformer, solve the heating problem of transformer, but also improve the stability, security and other technical performance of the system, so it is worth recommending and promoting.

Research on a New Stress Sensor Based on the Amorphous Alloy

Amorphous alloy material has good soft magnetic properties, so it can be used for stress measurement. At first, the working principle of the stress measurement was analyzed. Secondly its output characteristic mathematical model was established by adopting multivariate linear regression analysis method, and the simulation of the mathematical model was made based on Matlab. Finally a practice measurement with Fe-base TM—M Amorphous alloy was completed. The results of the test have showed that the stress measurement method has some characteristics of being sensitiveness to measure and simple to make a testing system, and a promising method of measuring stress.