Search

Grain-oriented (GO) electrical steel (ES) laminates are still very important in industrial applications due to their remarkable crystallographic properties. Cores of large electrical machines and transformers are built from ES. The performances of these devices are significantly influenced by the properties of ES. The improvement of ES properties has been the subject of considerable research for many years. The phenomenon of magnetic anisotropy is highly non-linear, and it should be taken into account by the designers of magnetic circuits. The article proposes a modified model for calculating the angular properties of specific total loss of ES. The modeling takes into account the isotropic component (from classic eddy currents) and the anisotropic component, which is the sum of hysteresis and excess losses. For the directional loss modeling, the Boltzmann function was used. An analysis of the dependency of model coefficients on the frequency is presented. [ABSTRACT FROM AUTHOR]

The effect of annealing treatment on the microstructure and texture of a Ti50Ni47Fe3 shape memory alloy tube was studied. The results show that the recrystallization process of a cold-rolled Ti50Ni47Fe3 alloy tube occurs at 600 °C. The microstructure changes from long striped grains to equiaxed recrystallized grains. The main texture of the alloy tube is the fiber texture <111> parallel to RD. With the increase in the annealing temperature, the crystal orientation of the alloy gradually turned to (111)<112>, and a series of secondary textures were distributed along the γ orientation line when the alloy was annealed at a lower temperature (450~600 °C). When the alloy was annealed at 650 °C, the growth of recrystallized grains made the grain orientation change, which led to the weakening of the γ-fiber texture and the formation of recrystallization textures. [ABSTRACT FROM AUTHOR]

{001}〈101〉 texture evolution in Ti–37 mol%Nb (Nb–46.5 mass%Ti) alloy was determined under plane strain compression at the temperatures of 800°C, 950°C, and 1100°C, in which preferential dynamic grain growth (PDGG) took place. At lower temperature and higher strain rate such as 800°C–10−2/s, almost no grain growth occurred in the transverse direction (TD), and the α-fiber + near {111}〈110〉 in the γ-fiber texture was developed, which was a stable orientation as deformation texture. At higher temperature and lower strain rate such as 1100°C–10−3/s, the grain growth along the TD remarkably appeared by grain boundary bulging, and an extremely high pole density of the texture near the α-fiber, especially the rotated cube {001}〈101〉, evolved. A planar dislocation structure with pile-ups appeared and individual dislocations were uniformly distributed in the grains. The rotated cube texture fulfills the conditions of the deformation stability and the low Taylor factor in accordance with the PDGG mechanism. The essential aspect of the mechanism is the preferential growth of grains with a stable orientation for deformation and a low Taylor factor in the given deformation mode. [ABSTRACT FROM AUTHOR]

The effect of final annealing temperature and time on the core loss, magnetic permeability, and magnetic anisotropy of a temper-rolled, semi-processed 0.5 wt.% Si non-oriented electrical steel was investigated. The magnetic properties of the steel sheets at 50–400 Hz and 0.5–1.50 T were measured by the Epstein frame method on strips cut along both the rolling (RD) and transverse directions (TD). Optimal magnetic properties were obtained when the annealing temperature was at 800–825°C, and the annealing time was 2–4 h. Relatively large magnetic anisotropy between the RD and TD was observed in samples after recrystallization (~ 10% in core loss and ~ 70% in relative permeability), while deformed and non-recrystallized samples showed small anisotropy in magnetic properties. Regardless of the processing state of the steel, i.e., temper-rolled, recovered, or recrystallized, the core loss followed quadratic polynomial functions with respect to both the frequency and magnetic flux density, while the relative magnetic permeability followed cubic polynomial functions with respect to both the frequency and magnetic flux density. The microstructure and texture of selected samples were characterized by electron backscatter diffraction, which revealed the correlations between the magnetic properties of the steel and the microstructure and texture. [ABSTRACT FROM AUTHOR]

By hot rolling Fe-2.5% Si-0.8% Al electrical steel slabs to total reductions of 52% and 88%, respectively, the formation of shear textures (Goss texture{110} < 100 > , brass texture{110} < 112 > , copper texture{112} < 111 >) with 52% reduction and the retention of {100} textures (cube texture{100} < 001 > , 25° rotated cube texture{100} < 021 > , rotated cube texture{100} < 110 >) with 88% reduction were analyzed. The results indicated that the orientation rotation of the initial grain in the surface layer region at 52% reduction only slowly approached the three orientations of the shear type texture. The reasons included many influencing factors, such as the coarse grain sizes, the interaction of surrounding grains, and the deviation of initial orientations to ideal < 001 > //ND orientations. The orientation rotations at 52% reduction were not as typical as at the large hot-rolling reductions. In addition, large regions of cube and 30°-rotated cube orientation could be retained in the central layer at 88% reduction. These phenomena were clearly different from the cold-rolling behavior of columnar grains. Compared with the central layer of industrial hot-rolled sheets, it was found that the < 001 > //ND fiber textures of laboratory hot-rolled sheets were retained more easily. [ABSTRACT FROM AUTHOR]

Rolling and annealing is a crucial technology to produce electrical steel sheets. This technology is not just aimed to control the geometry of steel sheets but more importantly to enhance the magnetic properties of the final products via appropriate microstructure and crystallographic texture. In this study, the evolution of microstructures and textures of an Fe-1.2 wt.% Si alloy through the entire processing route (from reheating, warm rolling to annealing) is monitored by electron back-scatter diffraction. Plastic flows of the material during conventional and asymmetric rolling are analyzed in detail based on geometric parameters of the rolling gaps. Deformation textures are accurately predicted by the full-constraint Taylor and advanced Lamel (ALAMEL) crystal plasticity models. The development of recrystallization textures is accounted for by the plastically stored energy in deformed crystals, which in turn is approximated by the plastically dissipated power (i.e., the Taylor factor) as predicted by the full constraint Taylor model. Although asymmetric warm rolling does not produce an improved texture or microstructure for electrical steels, the present study provides useful information on the evolution of the recrystallization microstructure and texture in steels with a complex strain history after asymmetric warm rolling. [ABSTRACT FROM AUTHOR]

Fe−6.5%Si has higher electrical resistivity, lower magnetocrystalline anisotropy, and lower magnetostriction than traditional Fe−3.2%Si silicon steel. The reduced iron losses of Fe−6.5%Si render it a highly favorable candidate for high-speed motors and transformers. However, large-scale production of wide Fe−6.5%Si tape by rapid solidification can be challenging mainly because of its high melting point. In this work, boron is alloyed to Fe−6.5%Si to reduce its melting temperature and interfacial energy to improve the alloy's processability. Boron additions from 0.01 wt.% to 2.24 wt.% into Fe−6.5%Si and its effect on ribbon thickness, grain size, magnetic, and mechanical properties were studied. Minor boron alloying significantly changed the melt pool stability and wetting on the quench wheel and in turn increased the quench rate with minimum impact on the magnetic saturation and ductility. Boron addition of < 0.06 wt.% was also found beneficial to the magnetic property of the alloy by lowering both its hysteresis and eddy current losses. [ABSTRACT FROM AUTHOR]

Three different grades of non-grain-oriented (NGO) steels in different conditions have been examined regarding the in-plane variation of their magnetic properties. The textures in these materials were determined by X-ray diffraction and processed as orientation distribution functions (ODFs). Complementary metallography was also carried out by optical microscopy and electron back-scattering diffraction (EBSD). The cubic harmonics approach based on textures using orientation distribution functions accords well with the induction values for different directions in the plane of the sheets. Power loss values fit broadly with the model but there are systematic deviations. In particular, power losses in the transverse direction (TD) are underestimated. Grain orientation maps were examined to look for aligned microstructures which might account for the deviations, but these could not provide an explanation. The textures are dominated by orientations for which <110> directions are clustered along the TD, and some of the domain boundaries in these grains have a special character and are not motivated by the applied field. It is proposed that the presence of these relatively static special boundaries hinders the movement of other mobile domain walls in the earlier stages of magnetization, so leading to the increases in the hysteresis and power losses for the TD tests. [ABSTRACT FROM AUTHOR]

{100}<0vw> texture is the favorable texture in non-oriented electrical steels (NOES). However, the conventional processes are difficult to produce NOES with strong {100}<0vw> texture. In this study, the 0.35 mm thick 3.1% Si NOES with strong {100}<0vw> texture was produced by the top-side pouring twin-roll casting, cold rolling with or without intermediate annealing, and final annealing process. The microstructure and texture were characterized by optical microscopy, X-ray diffraction and electron backscatter diffraction. Compared to the one-stage cold-rolled strip-cast NOES, the semi-processed (two-stage cold-rolled) strip-cast NOES with intermediate annealing at 650 °C and 700 °C have stronger {100}<0vw> texture and better magnetic properties. The reason is that the semi-processing method can avoid the encroachment on {100}<0vw> grains by other oriented grains, which can encroach on the {100}<0vw> grains by strain-induced grain boundary migration mechanism. Furthermore, the effect of intermediate annealing temperature on the microstructure, texture, and magnetic properties of the semi-processed strip-cast NOES were studied. [ABSTRACT FROM AUTHOR]

In response to the challenging difficult-to-deform of magnesium foils, a high-efficiency and high-precision electro-rolling temperature field coupled model is established. This model is designed to simulate the non-annealing electric rolling (NAER) process of Mg foils under conditions of high current density, rapid temperature rise rates, and large temperature gradients. Firstly, a coupled temperature field difference model for the guide roller, roll, and Mg foil is established, based on the equipment for NAER and the electrification conditions. The Joule heat, distortion heat, and friction heat in the electric rolling process were precisely considered. Secondly, considering the peculiarity of the heat source and the heat transfer mechanism during NAER, the influence of the dynamic boundary conditions on the instantaneous temperature of the Mg foil was analyzed, which was closer to the actual situation. The experimental results show that the original model can accurately simulate the transient temperature change in Mg foils during NAER, and the error between the predicted value and the measured value is within 7.1%. According to the calculation of the model, the microstructure of completely recrystallized magnesium foil with a grain size of 4.61 μm and a texture strength of 11.3 can be obtained at an inlet temperature of 250 °C. [ABSTRACT FROM AUTHOR]

Austenitic stainless steels are widely used in industry, from heavy industry and power generation to precision mechanics and electronics, accounting for about 2/3 of the stainless steels produced. The stability of austenite influences the properties and behaviour of these steels during deformation and annealing. This paper presents the results of research into austenitic metastable phase X5CrNi1810 steel, which was subjected to cold rolling (in the range of 5 to 80%) and then annealing (at temperatures of 500-900 °C). The research focused mainly on changes in crystallographic texture parameters occurring during the analysed processes. It was found that the observed development of the deformation texture is complex due to the fact that several processes take place simultaneously. Namely, the deformation of austenite, the transformation of austenite into martensite, and the deformation of the resulting martensite. The texture of the deformed austenite was similar to the texture of the alloy type {112}<110>. After 80% deformation, the Goss-type {110}<001> texture component showed the highest intensity. The lack of {112}<111> orientation in the texture was due to the fact that this orientation changes to the {112}<110> martensite orientation as a result of the γ → α' phase transition. Annealing of the deformed steel at 500 °C led to an increase in the degree of texturing (sharpening of the texture), which was related to the improvement of the texture in this temperature range. Above 600 °C, the degree of texturing decreased, which is directly related to the α' → γ reverse transformation and the subsequent recrystallization process. Magnetic studies indicate an increasing proportion of the magnetic phase α' (martensite) together with an increasing degree of deformation. For deformation of 80%, the amount of magnetic phase reached a value of more than 33%. After annealing at a temperature of 800 °C, there is no martensite in the structure, which indicates that, in these heat treatment conditions, the complete reverse transformation of martensite into austenite has already taken place. [ABSTRACT FROM AUTHOR]

The multi-scale mechanical characterization of nanostructured, innovative structural and functional materials, biomaterials, self-reporting and adaptive structures, hierarchically architectured systems, and miniaturized devices are intriguing due to their unusual and scale-dependent behavior. To unravel this, Smedskjaer's group[7] measured the fracture energy of six high Poisson's ratio oxide glasses, but no such relationship was observed between Poisson's ratio and fracture energy. Oxide glasses typically have a Poisson's ratio <0.3; however, the brittle-to-ductile transition that can also be seen in oxide glass is entirely unknown. Instead, they found a relation between Poisson's ratio and Young's modulus of oxide and metallic glasses. [Extracted from the article]

The paper presents the results of validating the model of anhysteretic magnetization curve of anisotropic soft magnetic materials utilizing the Boltzmann distribution of magnetic domain directions. It was confirmed that the editorial mistake in the original paper presenting the concept of anisotropic anhysteretic magnetization curve was reproduced in subsequent publications. Validation presented in the paper covers an anhysteretic magnetization curve model for magnetic materials with axial anisotropy and anisotropic grain-oriented electrical steels. However, the proposed correction of the model of the anisotropic anhysteretic magnetization curve can be extended to other types of anisotropy. [ABSTRACT FROM AUTHOR]

In the cold rolling process of steel strip products, strip breakage is an undesired production failure which can lead to yield loss, reduced work speed and equipment damage. To perform a root cause analysis, conventional physics-based approaches which focus on mechanical and metallurgical principles have been applied in a retrospective manner. With the advancement of data acquisition technologies, numerous process monitoring data is collected by various sensors deployed along this process; however, conventional approaches cannot take advantage of these data. In this paper, a machine learning-based approach is proposed to characterise and model strip breakage in a predictive manner. First, to match the temporal characteristic of strip breakage which occurs instantaneously, historical multivariate time-series data of a cold rolling process were extracted in a run-to-failure manner, and a sliding window strategy was adopted for data annotation. Second, breakage-centric features were identified from three facets – physics-based approaches, empirical knowledge and data-driven features. Finally, these features were used as inputs for strip breakage modelling using recurrent neural networks (RNNs), which are specialised in discovering underlying patterns embedded in time-series data. An experimental study using real-world data collected from a cold-rolled electrical steel strip manufacturer revealed the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

We report a bulk-sensitive x-ray magnetic microscope that exploits a new magneto-optical effect in x-ray emission, referred to as x-ray magnetic circularly polarized emission (XMCPE). An advantage of XMCPE is a large magnetic dichroic effect for 3 d transition-metal elements in the hard x-ray region, which enables the realization of a bulk-sensitive microscope suited to iron- and cobalt-rich ferromagnetic materials. We constructed a scanning microscope with 10 μ m lateral resolution. A key element is a Montel-type collimating mirror that widely collects the divergent x rays emitted from a sample and converts them into a well-collimated x-ray beam, which is required for circular polarization analysis. Owing to this mirror, the obtained XMCPE spectra of metallic iron exhibited strong intensity and a large magnetic dichroic effect. The performance of the microscope is also demonstrated by the acquisition of magnetization images of an electrical steel sheet with an insulating coating. [ABSTRACT FROM AUTHOR]

Highlights: Aligned graphene building blocks take full advantages of the outstanding properties of graphene. Comprehensive review of recent advancements in the utilization of highly aligned graphene aerogels for multifunctional applications. By systematically summarizing the controlled assembly, aligned structural attributes, quantitative characterization methods, anisotropic properties, and multifunctional applications of graphene aerogels, this review enhances understanding of the material's potential for diverse applications, offering tailored properties and novel functionalities. Stemming from the unique in-plane honeycomb lattice structure and the sp2 hybridized carbon atoms bonded by exceptionally strong carbon–carbon bonds, graphene exhibits remarkable anisotropic electrical, mechanical, and thermal properties. To maximize the utilization of graphene's in-plane properties, pre-constructed and aligned structures, such as oriented aerogels, films, and fibers, have been designed. The unique combination of aligned structure, high surface area, excellent electrical conductivity, mechanical stability, thermal conductivity, and porous nature of highly aligned graphene aerogels allows for tailored and enhanced performance in specific directions, enabling advancements in diverse fields. This review provides a comprehensive overview of recent advances in highly aligned graphene aerogels and their composites. It highlights the fabrication methods of aligned graphene aerogels and the optimization of alignment which can be estimated both qualitatively and quantitatively. The oriented scaffolds endow graphene aerogels and their composites with anisotropic properties, showing enhanced electrical, mechanical, and thermal properties along the alignment at the sacrifice of the perpendicular direction. This review showcases remarkable properties and applications of aligned graphene aerogels and their composites, such as their suitability for electronics, environmental applications, thermal management, and energy storage. Challenges and potential opportunities are proposed to offer new insights into prospects of this material. [ABSTRACT FROM AUTHOR]

FeSiCr/Al 2 O 3 modified powders were prepared by dry milling and coupling for different durations, and FeSiCr/Al 2 O 3 epoxy resin composites were prepared by banburying and low-pressure molding. The melt index, bending strength, magnetic permeability, and magnetic loss of the FeSiCr/Al 2 O 3 epoxy resin composites were measured. The microstructures of the different FeSiCr/Al 2 O 3 modified powders and FeSiCr/Al 2 O 3 epoxy resin composites were observed using scanning electron microscopy (SEM), and their effects on the flowability, magnetic, and mechanical properties of the composites are discussed. The results showed that dry milling and coupling modification greatly improved the flowability of the FeSiCr/Al 2 O 3 /epoxy resin composites. Moreover, the bending strength and effective magnetic permeability increased, and the core loss decreased. Based on the loss data, a new loss separation method that is different from the conventional low-frequency method is proposed. Residual, hysteresis, and eddy current loss were in descending order in the frequency range of 100–2000 kHz. [ABSTRACT FROM AUTHOR]

Adequate mathematical description of magnetization curves is indispensable in engineering. The accuracy of the description has a significant impact on the design of electric machines and devices. The aim of this paper was to analyze the capability of Bézier curves systematically, to describe the nonlinear static magnetic properties of non-oriented electrical steels, and to compare this approach versus the established mathematical descriptions. First, analytic functions versus measurements were analyzed. The Bézier curves were then compared systematically with the most adequate analytic functions. Next, the most suitable orders of Bézier curves were determined for the approximation of nonlinear magnetic properties, where the influence of the range of the input measurement dataset on the approximation process was analyzed. Last, the extrapolation capabilities of the Bézier curves and analytic functions were evaluated. The general conclusion is that Bézier curves have adequate flexibility and significant potential for the approximation and extrapolation of nonlinear properties of non-oriented electrical steels. [ABSTRACT FROM AUTHOR]

State-of-the-art soft magnetic (SM) alloy systems such as electrical steels and permalloys exhibit large eddy current losses at high-frequency (kHz range and above), limiting their application in fast switching devices. Eddy current losses can be reduced for metallic alloys through a decrease in characteristic length scale or embedding them in an insulation layer. This work proposes the development of fine-scale core materials consisting of metallic SM nano/microparticles with magnetic, inorganic insulation layers, and their synthesis using a wet chemistry-based, scalable method for high frequency and high-power applications. More specifically, a magnetic ferrite coating (Ni0.5-xMnxZn0.5Fe2O4, x = 0.0–0.5) was applied via deposition of ferrite powder produced using a "wet chemistry-based" co-precipitation method; the ferrite was distributed through the Fe micropowder via either ball milling or ultrasonic mixing. Powder cores were prepared by compaction of the synthesized composites. Relative magnetic permeability and core loss were measured at excitation frequencies to 200 kHz. A core loss of 127 kW/m3 was measured at excitation frequency of 100 kHz and magnetization of 0.02 T. This value improves on the 199.3 kW/m3 reported in literature at identical excitation conditions for a compact formed from a composite comprising Fe microparticles coated with low-permeability Ni0.5Zn0.5Fe2O4. Ultrasonic mixing resulted in slightly lower core loss than ball milling, possibly because ball milling causes loss-increasing deformation of the Fe micropowder. XRD and SEM were used to observe composite composition and core cross-section microstructure. [ABSTRACT FROM AUTHOR]

The magnetic properties of electrical steel sheets are strongly affected by the Multi-Physics Factors (MPF), such as bending stress, working temperature, and magnetization patterns. To investigate the complex magnetic properties of the material under MPF magnetizing conditions, a magnetic property measurement system is first developed, considering the effect of bending stress, temperature loading, and non-sinusoidal magnetization waveforms. Then, the magnetic and the loss properties of Grain-Oriented (GO) electrical steels under MPF magnetizing conditions are measured and discussed. Obtained results showed that bending stress and non-sinusoidal magnetization waveforms are positively correlated with the loss properties of electrical steel sheets, and elevated temperatures can mitigate the effects of bending stress and harmonics on magnetic properties and losses. [ABSTRACT FROM AUTHOR]

The shape and convexity are crucial quality assessment indicators for hot-rolled electrical steel strips. Besides bending rolls, shifting rolls, and the original roll profile, the thermal roll profile also plays a significant role in controlling the shape and convexity during the hot-rolling process. However, it is always overlooked due to its dynamic uncertainty. To solve this problem, it is necessary to achieve online cooling-status control for the local thermal expansion of rolls. Based on the existing structure of a mill, a pair of special partition-cooling beams with an intelligent cooling system was designed. For high efficiency and practicality, a new online predictive model was established for the dynamic temperature field of the hot-rolling process. An equivalent treatment was applied to the boundary condition corresponding to the practical cooling water flow. In addition, by establishing the corresponding target distribution curve for the partitioned water flow cooling, online water-flow-partitioning control of the thermal roll profile was achieved. In the practical application process, a large number of onsite results exhibited that the predicted error was within 5% compared to the experimental results. The temperature difference between the upper and lower rolls was within 5 °C, and the temperature difference on both sides of the rolls was controlled within 0.7 °C. The hit rate of convexity (C40) increased by 33%. It was demonstrated that the partition-cooling processes of hot rolling are effective for the local shape and special convexity. They are able to serve as a better control method in the hot-rolling process. [ABSTRACT FROM AUTHOR]

This paper presents a newly proposed domain wall energy-based model of the 2D strain dependence of relative magnetic permeability in highly grain-oriented anisotropic electrical steels. The model was verified utilizing grain-oriented M120-27s electrical steel sheet samples with magnetic characteristics measured by an automated experimental setup with a magnetic yoke. The model's parameters, identified in the differential evolution-based optimization process, enable a better understanding of the interaction between stress-induced anisotropy and magnetocrystalline anisotropy in electrical steels. Moreover, the consequences of the simplified description of grain-oriented magnetocrystalline anisotropy are clearly visible, which opens up the possibility for further research to improve this description. [ABSTRACT FROM AUTHOR]

Improvement of magnetic properties of electrical steel can be achieved by reduction the size of magnetic domains. The application of local stresses through laser scribing leads to reduced core losses. In order to determine the effect of laser refinement conditions of magnetic domains on the properties of the soft magnetic material, four samples with a thickness 0.23 mm were refined. The refinement of each sample was carried out using different line energies of the laser beam. Estimation of the magnetic domain size was performed using the Jeffries method, the magnetic viewer was used to reveal the domain structure. The measurement of the magnetic properties was performed at a frequency of 50 Hz and an induction of 1.5 T. The analyzed results presented in this work indicate impact of laser refining on magnetic properties of grain oriented electrical steel depending on used laser beam energy. [ABSTRACT FROM AUTHOR]

Changes in the microstructure and texture with annealing temperature of a nanostructured complex aluminum alloy fabricated by multi-stack Accumulative Roll Bonding (ARB) process using various Al alloys are investigated in detail. The ARB process is performed up to 4 cycles without lubrication at room temperature. The specimen fabricated by the ARB is a multi-layer aluminum alloy sheet in which the AA1050, AA5052 and AA6061 Al alloys are alternately stacked to each other. The average grain size of the starting material is 140 µm, but after 4 cycles of the ARB process, this is reduced to 150 nm. The complex Al alloy still shows an ultrafine grained microstructure at annealing temperatures up to 250°C, but after annealing at 300°C, it exhibits a heterogeneous structure containing both the ultrafine grains and the coarse grains due to the occurrence of discontinuous recrystallization. The specimens annealed at temperatures above 300°C also show a heterogeneous microstructure even if the heterogeneities of grain size differ from each other. The texture develops abnormally at higher annealing temperatures; the deformation textures are developed as [112]//ND and [111]//ND components, even in the recrystallized specimens. As the annealing temperature increases, the number fraction of the high-angle grain boundaries gradually decreases. The changes in microstructure and texture of the specimens with increase of the annealing temperature are compared to those of the specimens processed by 2-cycle of the ARB. [ABSTRACT FROM AUTHOR]

Magnetorquers are a very suitable solution for the nanosatellite's attitude and orbital control of low Earth orbit (LEO) given its constraints: small available volume, limited power consumption, and maximum weight limitation. In this work, an optimized ferromagnetic core magnetorquer is designed for LEO nanosatellites, considering the geometrical, electrical, and magnetic parameters in an electromagnetic finite element analysis (FEA). The final design dimensions are 10.9 mm diameter and 100 mm in length, with a ferromagnetic core made of high performance soft magnetic alloy Vacoflux50 measuring 5 mm diameter and 100 mm in length. Magnetorquer geometry has been optimized to achieve a very high compactness, reaching an optimal combination of high specific magnetic moment and magnetic moment-input power ratio at the same time. It shows a maximum magnetic moment of 1.42 Am², a magnetic moment-input power ratio of 2.52 Am²/W, and a specific magnetic moment of 22.5 Am²/kg, with a power consumption of 0.565 W and 0.5 A. Such a combination of high-performance values has not been previously found. Furthermore, it has displayed higher magnetic moment and specific magnetic moment than previous prototypes in literature. The simulated model is validated with the experimental testing of a manufactured prototype, by measuring the magnetic and electric variables. [ABSTRACT FROM AUTHOR]

Electrical steels are magnetically soft materials and are widely used in the electrical industry for the construction of power transformer cores, distribution transformers, current transformers, and voltage transformers. An important parameter of electrical components, which determines the efficiency of devices, is energy loss during remagnetization. Energy losses are caused by eddy currents, hysteresis, and magnetic delay associated with the low quality of the cut edge after the cutting of steels, and material deformations and excessive stress concentration in the surrounding cutting zones. Common techniques for cutting electrical materials in industrial lines include mechanical cutting and laser cutting. Work has shown that mechanical cutting of electrical steel single layers results in the occurrence of large deformation zones, and in cutting processes with a high-pressure abrasive water jet (AWJ), significant uplifts of material and burrs at the bottom edges of sheets occur. The problem of increasing the cutting quality was solved through selecting the stream parameters for bundle cutting of electrical steels. It has been shown that in the process of cutting electrical sheet bundles, the height of burrs on the cut surface and the zone of plastic deformation are reduced. The work also presents comparison and analysis of characteristic features of the cut edge of electrical sheets obtained through high-pressure abrasive water jet and mechanical cutting processes. The influence of the type and processing parameters on the characteristic features of the material hysteresis loop was determined. [ABSTRACT FROM AUTHOR]

This document is an editorial for a special issue of the journal "Materials" that focuses on "Soft Magnetic Materials and Their Applications." Soft magnetic materials are easily magnetized and demagnetized within magnetic fields and are used in electronics, energy conversion, and information processing. The special issue presents the latest advancements in the synthesis, characterization, and applications of soft magnetic materials, including soft ferrites, alloys, and composites. The papers cover topics such as improving high-frequency properties of soft ferrites, developing FeCo thin films for high-frequency electronic devices, and measuring and characterizing soft magnetic materials. The document discusses the applications of soft magnetic materials in electrical machines, motors, magnetic shielding structures, and atomic sensors. Various studies on the magnetic properties and performance of different soft magnetic materials are presented, suggesting their potential for enhancing the efficiency, sensitivity, and precision of electrical machines and sensors. The document concludes by acknowledging the authors and funding support for the research. [Extracted from the article]

The microstructural changes of hot-rolled electrical steel bands (HRB) produced by deformation and annealing have been recently reported. The effects of such changes on the microstructure and magnetic properties of steels obtained by further cold rolling and final annealing were not investigated. The present research reports the chemical and microstructural changes caused to HRB, by deformation and intercritical annealing, and their effect on the final microstructure and magnetic behavior of non-oriented electrical steel sheets. [ABSTRACT FROM AUTHOR]

In this study, the shape of laser welding parts required to develop a welding automation system was analyzed to improve the production process of thin-plate silicon–steel. During laser welding, a welding defect occurs in the welding area, resulting in beads. This can be measured and analyzed through computational fluid dynamics. When welding thin plates with a laser, precise parameter settings are required to reduce bead height and side effects to improve weld quality. Twelve simulation cases with different laser powers and scan speeds were carried out to compare bead heights. We discussed ways to improve the productivity of electrical steel sheets by applying data collected through simulations of a laser welding automation system. [ABSTRACT FROM AUTHOR]

The manufacturing processing of Electrical Steel Laminations (ESLs) for electric machines comprises cutting, stacking, and housing techniques which can result in plastic deformation and residual stress in the soft magnetic material. These manufacturing processes result in decreasing the magnetic quality and a local increase in both the static and dynamic hysteresis losses near the cut edges and consequently a reduction in the performance of the designed motor. The iron losses resulting from cutting can vary by a factor of two or more depending on geometrical, material, and processing parameters as well as the magnetic field strength. It is advantageous to consider these manufacturing effects in the design stage to reduce the probability of underperforming mass production. In this paper, the manufacturing processes of ESLs and their modelling methods are comprehensively surveyed. The gaps in scientific understanding and the research need for the expansion of accurate modelling of the cutting and joining of ESLs are subsequently discussed. [ABSTRACT FROM AUTHOR]

The nucleation and growth of {100}-textured and "toothed" columnar grains in Fe–0.5% Mn non-oriented electrical steels were analyzed by considering the factors like cooling rate and flowing rate of the hydrogen through phase transformation. The results demonstrate that the formation of {100}-textured and "toothed" columnar grains with high grain orientation spread (GOS) values mainly involved the nucleation of {100}-oriented nuclei with high GOS values on the surface region in the incipient stage of the γ (austenite) → α (ferrite) transformation and the growth of them caused by both directed growth along normal direction (ND) and faceted growth on the rolling surface (RS) during solid-state transformation. The morphology, size and structure characteristics of columnar grains are explained in terms of the competitions between the nucleation rate and the rate of directed growth along ND or faceted growth on RS of ferrite nuclei. When the nucleation rate of ferrite nuclei is equal to their directed growth rate along ND during the γ → α transformation, {100}-textured and "toothed" columnar grains with high GOS values are obtained. With a higher nucleation rate of ferrite nuclei than the directed growth rate of {100}-oriented nuclei along ND, three-layer sandwiched structure is formed, including few {100}-textured and "toothed" columnar grain layers with high GOS values on the surface, whereas large numbers of {111}-textured equiaxed grains with low GOS values in the inner layer. In addition, when the faceted growth on the RS of {100}-oriented nuclei is dominant, heavy and coarse "toothed" columnar grains with high GOS values are obtained. [ABSTRACT FROM AUTHOR]

The non-segmented shifted design of magnetic cores made of grain-oriented electrical steels, which induces the helical anisotropy, has been highly effective in reducing magnetic losses and minimizing acoustic noise in rotating machines. In order to address the challenges associated with precise theoretical modeling of complex underlying magnetization process, we have introduced angle-dependent first-order reversal curve diagrams. These diagrams offer significant insights into the microscopic properties of magnetization switching. By analyzing the distribution of coercive and interaction fields, we can identify distinct features that correspond to different domain wall processes and local coercivities, highlighting the magnetic behavior's heterogeneity. Through experimental measurements and theoretical analysis, we have gained quantitative understanding of the competing contributions from 90 ° and 180 ° domain wall processes in shifted structures. At shifting angles near the location of the hard magnetization axis, a notable transition in the magnetization process is observed by promoting the activation of the softer 180 ° domain wall processes. Among the different shifting angles tested, the structure with a shifting angle of 90 ° exhibits the highest ratio of soft-to-hard magnetization switching. [ABSTRACT FROM AUTHOR]

The authors analyze the possibility of separating total losses in electrical steel of magnetic circuits of electric machines into the following three components: losses caused by hysteresis, classical eddy currents, and anomalous eddy currents. The solution to this technical problem will make it possible to effectively design and construct electric machines with magnetic cores having low magnetic losses. Such separation is associated with time-consuming measurements using special equipment, and involves large errors. The following two methods have been suggested to determine losses in steel based on the existing dependencies of the above loss components on magnetization frequency and temperature: the three-frequency method and the three-temperature method. According to these methods, the loss components are determined based on the results of three no-load experiments carried out at three frequencies or at three temperatures of electric machine cores. The results of measuring the values of active power spent for core heating were used to calculate the power of losses caused by hysteresis, classical eddy currents, and anomalous eddy currents. The results of the experiments carried out by the three-frequency and three-temperature methods agree well with each other, thus confirming the adequacy of these methods and the possibility of their use in practice. The advantages and challenges of implementing each method have been analyzed. The methods can be used to effectively minimize losses in the steel of electric machines. [ABSTRACT FROM AUTHOR]

This paper describes an experimental setup used at the Czech Metrology Institute (CMI) to measure the specific power loss of oriented and non-oriented electrical steel sheets up to 1 kHz using an Epstein frame. Special attention is given to a) a description of the hardware that is used, b) a description of the feedback control and measurement software, and c) an analysis of the sources of uncertainty and validation. Calibration expanded uncertainty of (0.5 up to 1.6)% for k = 2 can be achieved with this setup. [ABSTRACT FROM AUTHOR]

Herein, the effect of annealing time on the texture evolution in Fe–3.4 wt% Si non‐oriented electrical steel is investigated. Strip samples are cast using a vacuum sampling method, which simulate the solidification conditions of an industrial twin roll thin strip casting (TRSC) process. As‐cast samples with different carbon and sulfur (C&S) levels are hot rolled (HR) with varying levels of hot deformation, cold rolled (CR) to 0.35 mm thickness, and then annealed at 1050 °C for different holding times (1, 6, 24 h). To Fe–3.4 wt% Si nonoriented electrical steel, the observed texture evolution can be divided into different stages as annealing time is increased from 1 to 24 h. With increasing annealing time, the fraction of Goss texture decreases initially and then increases again through the consumption of grains with other textures. With additional time, a decrease of pinning force due to precipitate coarsening results in normal grain growth, resulting in an increase of grain size. In this step, Cube grains can form from rotated Goss grains. A model for core loss is presented and used to explain the core loss results. [ABSTRACT FROM AUTHOR]

A novel PID-type fuzzy logic controller (FLC) with an online fuzzy tuner was created to maintain stable in situ control of the cutting front temperature, aiming to enhance the laser process for thin non-oriented electrical steel sheets. In the developed controller, the output scaling factors and the universe of discourse were initially optimized using a hybrid of the particle swarm optimization and grey wolf optimization methods. The optimal parameters obtained were utilized in experiments involving the laser cutting of thin non-oriented electrical steel sheets, compared to an open-loop control system maintaining a constant cutting speed. The PID-type FLC with an online fuzzy tuner demonstrated a superior cutting quality, generating a smaller roundness and a reduced heat-affected zone (HAZ) through the in situ tuning of control parameters. Particularly, the HAZ width was significantly smaller than that reported in a previous study which used fuzzy gain scheduling for temperature control. Moreover, the cutting time was diminished by optimally adjusting the cutting speed using PID-type FLC with an online fuzzy tuner. Therefore, the accumulated heat in the steel sheet, particularly under high laser pulse frequencies, was effectively reduced, making it suitable for industrial applications. [ABSTRACT FROM AUTHOR]

The present study tries to refine the microstructure of hot-rolled C-Mn steels via ferrite dynamic recovery or recrystallization. A total of 1.5 wt.% Al is added to C-Mn steel (1.5Al steel) to retain a certain amount of ferrite at high temperatures so that ferrite dynamic recovery or recrystallization occurs during the hot rolling process. 0.022 wt.% Nb and 0.018 wt.% Ti are further added (1.5Al-NbTi steel). The results show that ferrite dynamic recrystallization occurs entirely during the hot rolling process of the 1.5Al steel, but the microstructure is not refined. Ferrite dynamic recrystallization is suppressed by adding Nb and Ti elements, owing to the pinning effect of NbC and TiC precipitates. A dynamically recovered microstructure containing subgrains with a volume fraction of 29.7% is formed in the 1.5Al-NbTi steel, and the size of subgrains ranges from 1 to 4 μm. Some refined ferrite grains surrounded by high-angle grain boundaries of 2 to 5 μm also form due to ferrite dynamic recrystallization. Moreover, adding 1.5 wt.% Al reduces the yield strength from 291 ± 1 (C-Mn steel) to 246 ± 2 MPa. Furthermore, adding Nb and Ti improves the yield strength to 349 ± 3 MPa (1.5Al-NbTi steel). This work indicates that refining the microstructure of hot-rolled steels is feasible by ferrite dynamic recovery and dynamic recrystallization. [ABSTRACT FROM AUTHOR]

The paper intends to study the magnetic losses of non-oriented electrical steel laminations under sinusoidal voltage supply. The measurement of magnetic losses of electrical steel laminations in Epstein Frame is implemented step by step at frequency range from 50 Hz. The calculation of the magnetic losses is made by using two methods based on the statistical loss model. Our contribution consists on the first model which corresponds to the curve fitting method which needs many experimental data but allows a better exactitude. The second method is defined in a time domain, in order to account of the presence of harmonics in the flux density wave form. The coefficients of the second method are determined from the curve fitting. A good agreement between practice and theory was established with these two methods. [ABSTRACT FROM AUTHOR]

In this study, the plastic deformation of pure copper under room-temperature compression and different annealing times was examined, and the microstructure and texture evolution were studied via scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and microhardness tests. The results showed that when the deformation degree was 93.75%, the microhardness increased from 76 HV (Vickers hardness) before deformation to 110 HV. After annealing, the hardness decreased with increasing annealing time, and the pure copper grain size could be refined from 150 μm to 6.15 μm. An increase in annealing time did not continue to promote recrystallization, while the effect on grain refinement was weakened. The geometrically necessary dislocation (GND) density decreased from 6.0 × 1014/m2 to 4.83 × 1014/m2 after annealing, which implies that static recrystallization occurs at the cost of dislocation consumption during the annealing process. The compression deformation of pure copper produced a strong deformation weave (<001> orientation), and a portion of the deformation weave within the material was transformed into a recrystallization weave (<111> orientation) after the annealing process. [ABSTRACT FROM AUTHOR]

This paper proposes an advanced approach to construct static hysteresis loop of Grain-Oriented (GO) electrical steels for dynamic modeling and energy loss analysis. The proposed approach is in line with the magnetic hysteresis and phenomenological concepts of rate-dependent and rate-independent energy loss components of ferromagnetic materials under time-varying magnetic fields. The proposed method can predominantly describe energy loss mechanism and magnetization processes of the material. Accuracy of this technique was validated on Epstein size laminations of 3% GO silicon steels. The results explicitly confirmed the effectiveness of the proposed method in dynamic hysteresis modeling of GO electrical steels at magnetizing frequencies up to 1 kHz and peak flux densities up to 1.7 T. [ABSTRACT FROM AUTHOR]

This paper presents a semi-analytical homogenization model for Soft Magnetic Composites (SMCs), providing the effective magnetic behavior and the level of Eddy Current (EC) losses. Both linear and nonlinear magnetic behavior are considered. A magnetic circuit made of SMC is then modeled with a Finite Element Model (FEM). The size of heterogeneities of SMC being much smaller than the device size, the proposed approach relieves the burden of a very fine mesh in the FEM, by using the effective properties of an equivalent homogeneous material. The approach is validated by comparing the results on the homogenized magnetic circuit with the ones obtained from a computationally heavy FEM describing the heterogeneities with a very fine mesh. The results show that the homogenized model provides a very accurate description of the magnetic behavior and EC losses of SMC for both linear and nonlinear cases. [ABSTRACT FROM AUTHOR]

InAs-On-Insulator (InAs-OI) structures fabricated by the Smart Cut process are promising for three-dimensional (3D) integration of complementary metal–oxide–semiconductor devices owing to the low thermal budget, high mobility, and low contact resistance. InAs-OI structures are also expected to reduce the leakage current and parallel conduction channels in InAs n-channel MOSFETs, which are serious problems. Smart Cut is a promising way to integrate III–V semiconductors on Si substrates for 3D integration. However, the electrical characterization of InAs-OI films realized by Smart Cut has not been reported yet. In addition, since InAs-OI's crystallinity is severely degraded by passage of a large amount of H+ ions in the Smart Cut process, we need to study the effects of thermal annealing on the electrical properties of the InAs-OI layers. It is found from the annealing temperature dependence of the electron concentration and the mobility that annealing at 500 °C significantly recovers InAs-OI crystallinity. Here, bulk and interface electrical properties are separately evaluated from the InAs-OI thickness dependence on the electron concentration and the sheet conductance. As a result, fabricated InAs-OI has the electron density of (6.3 ± 1.4) × 1017 cm−3 in the bulk region for an intrinsic donor InAs wafer and the high bulk mobility of 5800 ± 900 cm2/V s, indicating the high crystallinity of InAs-OI after 500 °C annealing. Also, the reusability of donor InAs wafers without degradation of InAs-OI film quality, which is one of the most important points for Smart Cut, is demonstrated by using (111) InAs donor wafers, attributed to much smoother (111) InAs-OI surfaces after splitting than (100) InAs-OI ones. [ABSTRACT FROM AUTHOR]