Amorphous Alloy Strips Research Articles

Fracture Behavior of Sandwich-Structured Fe-Based Amorphous Alloy Strip and ABS Polymer Composite Laminates

Fracture Behavior of Sandwich-Structured Fe-Based Amorphous Alloy Strip and ABS Polymer Composite Laminates

Plasticity and brittleness of Fe-based amorphous alloy strips assessed via a single abrasive impact method

Fe-based soft magnetic amorphous alloys represent the next generation of magnetic core materials and are expected to replace silicon steel sheets in many applications. An economical and fast methodology for the study of the plasticity and brittleness of this material is however necessary to permit its widespread use. Abrasive water jetting is a cold processing technique that has great potential for use in the fabrication and inspection of Fe-based amorphous alloy parts. However, research on this technique is currently lacking. In order to assess the plasticity and brittleness of Fe-based amorphous alloys by considering abrasive impacts, this work investigates the effect of impact speed and impact angle on the removal process in Fe-based amorphous alloys and establishes the corresponding abrasive erosion mechanism. It is found that Fe-based amorphous alloys exhibit four primary responses: shear slip, viscous flow, shear crack formation, and brittle fracture; the plasticity and brittleness of Fe-based amorphous alloys are assessed by considering the impact morphology and mechanism.

Ultrasonic-Assisted Shearing Characteristics of Fe-Based Amorphous Alloy Strips

Ultrasonic-Assisted Shearing Characteristics of Fe-Based Amorphous Alloy Strips

Magnetic properties and vibration characteristics of amorphous alloy strip and its combination

Although the cores made with amorphous metal alloy have lowered no-load losses compared with the orientation silicon steel cores, a high cost and noise level are inevitable because the magnetostriction for amorphous metal alloy strip is larger than the ordinary one. This study mainly focused on the experimental systems and methods for magnetic properties measurement, vibration characteristics and noise level of amorphous alloy strip and combinations. The vibration characteristics and noise level of amorphous alloy composite strip were also studied. The influence of the annealing process on magnetic energy, vibration characteristics and noise level of amorphous alloy core were analysed in detail as well. All the testing results and analysis above are helpful for the transformer manufacturers, and they can replace the expensive amorphous alloy metal strip with the combinations to reduce the noise and cost of the cores.

EFFECT OF ANNEALING AT DIFFERENT TEMPERATURES ON THE STRUCTURE AND HARDNESS OF AL85Y8NI5CO2 ALLOY AMORPHOUS STRIPS

Aluminum-based metallic glasses are the new promising family of materials. However, the effect of heat treatment on the structure and properties of Al–Y–Ni–Co amorphous alloys has not been widely studied so far. In this paper, Al85Y8Ni5Co2 amorphous alloy strips were obtained by hardening on a rotary copper wheel. The effect of vacuum annealing at temperatures ranging from 100 to 500 °C for 30 minutes on the structure and hardness of these strips was investigated. Transmission electron microscopy, X-ray diffraction analysis, and differential scanning calorimetry were used to study changes in the structure of strips after heat treatment. Vickers microhardness was measured to investigate the effect of annealing on the mechanical properties of strips. The results obtained allowed for the conclusions made about changes in hardness depending on the Al85Y8Ni5Co2 alloy strip structure. It was found that as the temperature rises, strip microhardness increases reaching a maximum value of 575±7 HV after annealing at 350 °C, then it decreases with a further increase in the annealing temperature. It was shown that the Al85Y8Ni5Co2 alloy strips remain completely amorphous and no crystalline phases are detected in their structures after annealing at temperatures up to 250 °C for 30 minutes. A sharp increase in hardness after annealing at 350 °C is associated with 10–30 nm nanocrystals of an aluminum solid solution formed in the amorphous matrix and surrounded by a residual amorphous matrix, while further hardness decrease is associated with the increasing sizes of these crystals and Al3Y and Al19Ni5Y3 intermetallics formed in the structure.

Production of Amorphous Alloys for Cybernetic Circuits

The ways in which the manufacturing conditions affect the magnetic (domain) structure of amorphous alloy strip produced on cooled disks are studied. On that basis, the physical properties of the alloys may be optimized for their intended use.

Life Cycle Environmental Impact Assessment of Amorphous Alloy Strips Production

Amorphous alloy strips has been widely used in the field of distribution transformers due to its good soft magnetic properties. The resources, energy consumption of the amorphous alloy strips production with the rapid solidification technique and the environmental impacts were calculated based on the life cycle assessment method. The results showed that the largest contribution to the non-renewable resource consumption was ferroboron production process, accounting for 98% of abiotic resource depletion (ADP). And the strip production process had the largest contribution to the global warming potential (GWP), acidification potential (AP), photochemical oxidation potential (POCP), human toxicity potential (HTP),eutrophication potential (EP). Ferroboron production process contributed the biggest environmental impact when producing 1 ton amorphous strip, accounting for 70% of the total environmental impact. Under the new technology for energy-saving and emission-reduction, when the utilization rate of boric acid increased in ferroboron production process, all the environmental impact decreased.

Warm Rolling Technique for Amorphous Alloy Strip Produced by Ultrarapid Cooling-Thermal Spraying Based on Hydraulic-Stress-Induced Structural Relaxation

Amorphous alloys have many superior properties such as high tensile strength,anticorrosion and easy soft-magnetism, but few amorphous alloys have been used as final productsbecause they lack plasticity at room temperature. Thus, we have developed a new amorphous alloyrolling method. Although the amorphous alloy was brittle at room temperature, it has deformedplastically by semisolid rolling under hydraulic stress. After being subjected to ultrarapidcooling-thermal spraying, amorphous alloy strips were rolled with a ditch roll in the viscoelasticregion below the glass transition temperature. Using this rolling method, we successfully preformedstrips for use in fuel cell separator. This rolling technique is based on the principle of stress-inducedstructural relaxation under hydraulic stress.

The world’s first wide and thick amorphous alloy coils produced using a new ultra-rapid cooling transition-controlled large-scale thermal spray gun

Amorphous alloys have high tensile strength and easy soft magnetization, and are corrosion-resistant. As conventional amorphous alloy strips are mainly produced by the single rolling method, their thickness is less than 100 µm and their width is less than 200 mm. By combining ultra-rapid cooling, large-scale thermal spraying and warm rolling, the world’s first ever amorphous alloy strips were produced with thickness exceeding 300 µm and width exceeding 300 mm.

Modelling and simulation of twin-roll casting of bulk metallic glasses

As an economic and direct route to continuous thin strip production from the melt, twin roll casting (TRC) has been established as an effective process for aluminium alloys. Its adaptation to casting of bulk amorphous alloy strip necessitates matching of the thermal and mechanical behaviour of the cooling multi-component melt to the requirements (especially cooling rate, and strip exit temperature and thermal gradient) of vitrification. Using a dedicated control volume numerical model of TRC, simulation of the casting of 2 mm thick Vit 1 (Zr41.2Ti13.8Cu12.5Ni10Be22.5) alloy strip shows that the acceptable casting speeds are in the range 2.5 to 3.5 cm/s. The effects of varying strip thickness and strip-roll heat transfer coefficient (HTC) on this casting window are assessed. The differences between modelling of conventional alloy solidification and metallic glass formation are presented.

Magnetic properties of amorphous alloy strips fabricated by planar flow casting (PFC)

The effects of nozzle-wheel gap size and annealing temperature on magnetic properties of FeSiB amorphous alloy strips fabricated by the PFC method were investigated. 50mm wide amorphous alloy strips were prepared by single-roll PFC equipment with various nozzle-wheel gap sizes and annealing temperatures. The decreasing nozzle-wheel gap size improved the magnetic properties of amorphous alloy strips by decreasing the eddy current losses and the easy magnetization. In addition, magnetic properties of annealed amorphous alloy strips primarily depended on size and volume fraction of nano-sized crystallites, which were closely related to annealing temperature.

Fe계 나노결정 분말코아의 연자성특성에 미치는 입도제어 및 바인더 첨가의 영향

The amorphous alloy strip was pulverized to get a flake-shaped powder after annealing at for 90 min and subsequently ground to obtain finer flake-shaped powder by using a ball mill. The powder was mixed with polyimide-based binder of , and then the mixture was cold compacted to make a toroidal powder core. After crystallization treatment for 1 hour at , the powder was transformed from amorphous to nanocrystalline with the grain size of . Soft magnetic characteristics of the powder core was optimized at with the insulating binder of 3wt%. As a result, the powder core showed the outstanding magnetic properties in terms of core loss and permeability, which were originated from the optimization of the grain size and distribution of the insulating binder.

Influence of heat treatment on the magnetic and piezomagnetic properties of amorphous and nanocrystalline Fe64Ni10Nb3Cu1Si13B9 alloy strips

FINEMET type alloy with substitution of 10 at.% of iron by nickel is studied from the point of view of the influence of the nanocrystallization process on the magnetic and magnetoelastic properties. Strip-shape samples of Fe 64 Ni 10 Nb 3 Cu 1 Si 13 B 9 amorphous alloy were annealed in vacuum for 1 h in the temperature range of 350–550 °C. Hysteresis loops were measured in order to determine the amount of anisotropy energy and corresponding anisotropy field, and coercive field of each annealed sample. This coercitivity reaches a minimum (about 5 A/m) after annealing at 460 °C. Magnetic field dependencies of magnetoelastic properties were also investigated. We have found a maximum value of the Δ E effect and magnetomechanical coupling coefficient of 61% and 0.85, respectively, that are accompanied by a minimum value of the quality factor of about 2 for the sample annealed at 460 °C. Such good parameters are related with internal stress relief and structural relaxation of the samples. The subsequent drop of the magnetoelastic coupling coefficient for higher annealing temperatures is related directly with a drop on the magnetostriction value, from (22–26) × 10 −6 to 13 × 10 −6 , due to the formation of a nanocrystalline structure in the samples. On the other hand, ultrasound velocities, measured at magnetic saturation of each sample, increase continuously between 4.9 and 5.6 km/s as the annealing temperature of the sample increases.

Remotely interrogated temperature sensors based on magnetic materials

A family of remotely interrogated passive temperature sensors is presented. These sensors are comprised of several layers of magnetic materials having either a resonant frequency or harmonic spectrum which varies with temperature. By incorporating a magnetic bias layer and a magnetically permeable layer, it is possible to create sensors which respond to a temperature threshold (reversibly or nonreversibly) or produce a signal which continuously and monotonically varies with temperature. In this paper, a 30%/70% Ni-Fe layer was used in conjunction with amorphous alloy strips to produce three distinct types of wireless temperature sensors operating over the range 20/spl deg/-70/spl deg/C.

Interactions between Bias Magnetic Tape and Amorphous Magnetostrictive Strip used as a Magnetic Tag Device

The magnetic characteristics of a magnetic tag device composed of a magnetostrictive strip and a bias magnetic tape were investigated with the purpose of finding the optimum material properties for use as a remote readable data carrier. We found that the magnetostrictive strip in the device assumes a maximum magnetomechanical coupling coefficient at an optimal strength of bias magnetic field, that varies along the length of the strip and is generated by the magnetic tape with appropriate thickness. The results are explained by a simple model where the strip is regarded as a linear array of rectangular domains. The model leads to the following conclusions: (1) the average direction of the local magnetization of a domain is determined by the bias magnetic field generated by the magnetic tape, and (2) an optimum value of the magnetic tape thickness exists, which gives the maximum coupling coefficient irrespective of the characteristics of the amorphous alloy strip. The most appropriate bias magnetic field by the magnetic tape is about 850 A/m in this study.

微量TiによるFe-B-Si系非晶質合金の磁気特性の劣化

The impurity Ti (0.02-0.2 mol%) in Fe-B-Si amorphous alloys prepared by the melt spinning method was found to deteriorate extremely the iron loss, W13⁄50, and the magnetic flux density at 100 A/m, B1.When the Ti concentration in an amorphous alloy strip was more than 0.05%, the α-Fe crystalline layer was detected on the free-side surface of the as-cast strip by X-ray diffraction, but not on the roll-side surface. This surface crystalline layer results partially in the deterioration of the magnetic properties through the magnetostriction, because it applies the compressive stress to the strip. According to X-ray diffraction and differential thermal analysis, the as-cast strip was in an amorphous state except the surface crystalline thin layer.The magnetic property of Ti-containing amorphous alloy strip annealed in the magnetic field was not improved to the extent of the pure Fe-B-Si amorphous strip, even after removal of the surface crystalline layer by chemical polishing. The internal magnetic field and the direction of the magnetic moment in the amorphous alloys changed with the addition of a small amount of Ti according to the Mössbauer spectra, so it was suggested that the main mechanism of the deterioration was the solute Ti in the amorphous alloys, but not the crystallization.

Transformer Applications of Amorphous Alloys in Power Distribution Systems

The need for more efficient transformer core materials, due to increased recognition by electric utilities of the costs of system losses, has spurred the development of amorphous alloy usage in power transmission and distribution transformers. Amorphous alloy core fabrication, as it relates to single-phase distribution transformer operating characteristics, is discussed. The effects of winding tension, a superior core annealing technique, and other annealing parameters are included. The potential use of Powercore??? consolidated amorphous alloy strip in three-phase stacked core transformers is also discussed in terms of the magnetic and physical characteristics of this newly developed amorphous core material. The most recent data on the thermal stability of amorphous core alloy magnetic properties are also summarized. These data confirm that core loss degradation is not expected to occur under typical transformer operating conditions and life.

Transformer Applications of Amorphous Alloys in Power Distribution Systems

The need for more efficient transformer core materials, due to increased recognition by electric utilities of the costs of system losses, has spurred the development of amorphous alloy usage in power transmission and distribution transformers. Amorphous alloy core fabrication, as it relates to single phase distribution transformer operating characteristics, is discussed. The effects of winding tension, a superior core annealing technique, and other annealing parameters are included. The potential use of POWERCORE™ consolidated amorphous alloy strip in three phase stacked core transformers is also discussed in terms of the magnetic and physical characteristics of this newly developed amorphous core material. The most recent data on the thermal stability of amorphous core alloy magnetic properties are also summarized. These data confirm that core loss degradation is not expected to occur under typical transformer operating conditions and life.

High frequency magnetic properties of some amorphous alloys

Amorphous magnetic alloys, although possessing low coercive forces and high electrical resistivities, have high-frequency losses significantly larger than expected from classical calculations. These high anomalous losses are caused by the wide domains in the material. This paper discusses some techniques for lowering the losses by changing the domain size in several amorphous alloy strips. Both DC and AC test (60 Hz, 1-10 kHz) results are reported. Transverse scratching, causing demagnetizing effects, lowered the loss, while longitudinal scratching had no effect. A transverse field during annealing led to a lower loss, as did annealing so that fine crystalline α-Fe precipitates were formed; such precipitates had a much stronger effect than did the induced magnetic anisotropy from field annealing. The application of a transverse DC bias field during testing at high frequency had a profound effect; losses decreased at low levels of bias field and increased at high levels. Application and removal of the bias field lowered the losses at high frequency as much as 40%. These bias fields were found to reduce the domain wall spacing. The observed effects are all consistent with the idea that domain refinement leads to a reduction in losses. Such processes can be used to improve the useful properties of amorphous alloys.

Fracture of Ni-Fe base metallic glasses

The fracture toughnesses of specimens of three transition metal base metallic glasses, Ni48Fe29P14B6Al3, Ni39Fe38P14B6Al3 and Ni49Fe29P14B6Si2 are reported. Each alloy was tested in a characteristic thickness, i.e., 25μm (Ni48), ∼ 43μm (Ni39) and ∼ 72 μm (Ni49) andK C values of ∼ 120, 62 and 30 kg mm−3/2, respectively, were observed. It is suggested that this variation is associated primarily with a transition from plane strain (K IC ≃ 30 kg mm−3/2) toward plane stress conditions as sample thickness is decreased. The fatigue crack propagation rate in the Ni39 alloy is also reported;da/dn (mm/cycle) ≃ 2×10−8 ΔK 2.25, whereΔK has units of kg mm−3/2. When the respective data are plotted in terms of (ΔK/E), whereE is Young's modulus, the crack growth behaviour for the Ni-Fe glasses approximates that for crystalline ferrous alloys. A classical chevron pattern, macroscopically at 90° to the tensile axis, is observed when amorphous metallic alloy strips fracture under plane strain conditions. On a finer scale, the chevrons exhibit a sawtooth structure, and the sawtooth surfaces show a fine scale, equi-axed vein pattern. This indicates that local failure occurs by shear rupture.