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The paper presents the results of testing the wear resistance and coefficient of friction (COF) tools made of SikaBeresin® F50 polyurethane resin intended for dies and punches for the cold sheet metal forming process. Seven sets of composite tools (rotating rings) additionally reinforced with waste metallic powders from Al and Cu alloys (5-20% by volume) from the dry cutting process of pipes and rods were tested. Wear resistance tests and determination coefficient of friction were carried out using the T-05 block-on-ring tribotester. The tests were performed for heat and corrosion resistant sheets made of nickel alloy AMS5599 (Inconel 625), iron alloy AMS5510 (321) and aluminum alloy sheets AMS4026 (6061-T4). Composite tools with the addition of 20% aluminum powder (A+B+C+20%Al) tested with a specimen of steel alloy AMS5510 and nickel alloy AMS5599 were characterized by the lowest wear resistance. In each case, the composite rotating ring without reinforcements was characterized by the lowest coefficient of friction. The use of Cu powder reinforcements in each case had a positive effect on increasing wear resistance. The best wear resistance of 0.011% was obtained for composite rotating ring with the addition of 10% copper powder paired with specimen of nickel alloy AMS5599 sheet. [ABSTRACT FROM AUTHOR]

The modified 9Cr–1Mo steel and Inconel (IN) 617 superalloy are high‐temperature alloys of prime importance in several industrial applications. Both of these are used at elevated temperature for various piping and tubing components and undergo asymmetric cyclic loading; therefore, it is highly essential to assess their resistance to accumulation of inelastic strain (ratcheting) under asymmetric stress cycling. In this study, ratcheting behavior of these alloys is compared at the homologous temperature of 0.42, under uniaxial asymmetric stress loading with positive mean stress. Deformation behavior of the tested samples is analyzed by transmission electron microscope. While there is homogeneous deformation in the modified 9Cr–1Mo steel, there is intersection of slip bands and presence of dislocation tangles in the IN 617 alloy. Fracture surface of the modified 9Cr–1Mo steel, tested under asymmetric cyclic loading, reveals typical ductile fracture resulting from tensile loading, whereas there is characteristic fatigue fracture of the IN 617 alloy. [ABSTRACT FROM AUTHOR]

Flux-cored arc welding (FCAW) is a universal group of welding methods in terms of the scope of application and automation possibilities, the share of which in various industries in many countries is still increasing. The paper presents the results of bibliographic analyses (scientometric analysis with the use of VOSviewer, Bibliometrix and CitNetExplorer tools) of a data set of 993 publications indexed in the Web of Science database on the subject of FCAW for all types of flux-cored wires. An objective and unbiased approach to analysis resulted in a relatively neutral assessment of the state of knowledge in the field of FCAW and allowed for the identification of research directions carried out in the world, the dynamics of their changes as well as research gaps and needs. The scientometric analysis approach provided a holistic picture of the development of FCAW over the last 58 years, pointing to the geographical areas where this process has been and is most intensively researched, the agencies funding this research, the most active research teams, as well as the journals that have most often published articles on this topic. The most current research directions in relation to FCAW include underwater welding, hardfacing and cladding purposes, health and safety issues, and more general topic: properties and weldability of ferrous alloys. However, among the most urgent research needs the following topics: fatigue analysis of welded joints, environmental degradation of flux-cored wires, properties and weldability of nickel alloys, development of hybrid and combined welding procedures can be listed. [ABSTRACT FROM AUTHOR]

SUMMARY: The seismic anisotropy of the Earth's solid inner core has been the topic of much research. It could be explained by the crystallographic preferred orientation (CPO) developing during convection. The likely phase is hexagonal close-packed iron (hcp), alloyed with nickel and some lighter elements. Here we use high energy synchrotron X-rays to study CPO in Fe-9wt%Si, uniaxially compressed in a diamond anvil cell in radial geometry. The experiments reveal that strong preferred orientation forms in the low-pressure body-centred cubic (bcc) phase that appears to be softer than pure iron. CPO is attributed to dominant {110}<111> slip. The onset of the bcc→hcp transition occurs at a pressure of ≈15 GPa, and the alloy remains in a two phase bcc + hcp state up to 40 GPa. The hcp phase forms first with a distinct {11 $\bar{2}$ 0} maximum perpendicular to compression. Modelling shows that this is a transformation texture, which can be described by Burgers orientation relationship with variant selection. Experimental results suggest that bcc grains oriented with <100> parallel to compression transform into hcp first. The CPO of the hcp changes only slowly during further pressure and deviatoric stress increase at ambient temperature. After heating to 1600 K, a change in the hcp CPO is observed with alignment of (0001) planes perpendicular to compression that can be interpreted as dominant (0001)<11 $\bar{2}$ 0> slip, combined with {10 $\bar{1}$ 2}< $\bar{1}$ 011> mechanical twinning, which is similar to the deformation modes suggested previously for pure hcp iron at inner core conditions. [ABSTRACT FROM AUTHOR]

High-speed electric motors, e.g., axially laminated anisotropic synchronous reluctance motors (ALA-SynRM), use a solid rotor manufactured by joining alternating layers of magnetic and non-magnetic metallic sheets. The strength of the dissimilar metallic joints is critical for the rotor's ability to withstand the operating conditions of the high-speed electrical machine. In this work, various dissimilar metallic joint configurations that can be used in high-speed ALA-SynRM rotors are studied by analyzing the shear strength, microstructure, hardness, and composition of the joints. Metallic joints of structural steels and Inconel® alloys fabricated by vacuum brazing and hot isostatic pressing (HIP) are studied. Finite element analysis (FEA) was performed to calculate the maximum shear stress of the joints that were subjected to various high speed operating conditions. The shear strength of the test specimens was measured and compared with FEA results. The microstructure and chemical composition of the joints were studied by using optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) on SEM. The results show that the hot isostatic pressed S1100MC-IN718 joint achieved the highest ultimate shear strength (233.3 MPa) followed by vacuum brazed S355MC-IN600 joint (230.1 MPa) and HIP S355-IN718 (203.5 MPa), thereby showing that vacuum brazing and HIP can be viable manufacturing methods to fabricate a high-speed ALA-SynRM rotor. [ABSTRACT FROM AUTHOR]

In the domain of the equipment and apparatus construction, a permanent preoccupation worldwide is ensuring technical performances and high fiability in exploitation. The users' requirement growth in this field led to producing materials with high characteristics such as iron-nickel alloys having a high nickel content with special magnetic, thermal, or elastic properties. The theoretical and experimental researches had the aim of obtaining cold rolled strip, thin (2.6 mm) and narrow (86 mm) from iron-nickel alloys with 41% Ni (low content of C: 0.02-0.04%; Fe: 58%; other elements: Mn, Si, Cu, Cr, Al: under 1%). Our own experiments aimed to establish an optimal cold rolling technology of hot rolled strips of iron-nickel alloys, in order to obtain cold rolled strips with superior mechanical and technological characteristics, strip profile according to current standards, including a finished product characterization. [ABSTRACT FROM AUTHOR]

The regularities of the grain structure formation of the austenitic phase in the ribbon of the metastable iron-nickel alloy Fe-31.4% wt. Ni-0.05% wt. C, formed in the conditions of high temperature gradients during quenching from the melt and its influence on the realization of martensitic γ-α-transformation in the local regions of the formed ribbon are investigated. The dependence of the completeness of the martensitic transformation and morphology of martensite crystals on the grain size of austenite is analysed. The change in the relative intensity of the diffraction reflexes of the γ-phase lines along the depth of the ribbon is characterized by a continuous change in the degree of austenite texture. The consequences of the influence of relaxation processes during the crystallization of the ribbon on the value of residual stresses, the presence of triple 120° joints between the grains as signs of equilibrium, and the change in their number along the ribbon are investigated. [ABSTRACT FROM AUTHOR]

We compare ferromagnetic resonance measurements of Permalloy Ni80Fe20 (Py) films sputtered onto Cu(111) films with and without a graphene (Gr) interlayer grown by chemical vapor deposition before Py deposition. A two-angle sputtering method ensured that neither Gr nor Py was degraded by the sample preparation process. We find the expected damping enhancement from spin pumping for the Py/Cu case and no detectable enhancement for the Py/Gr/Cu case. Since damping is sensitive to effects other than spin pumping, we used magnetometry to verify that differences in Py magnetostatic properties are not responsible for the difference in damping. We attribute the suppression of spin pumping in Py/Gr/Cu to the large contact resistance of the Gr/Cu interface. [ABSTRACT FROM AUTHOR]

Spectroscopic signatures of cased high-explosive charge denotations are examined using emission spectroscopy with sub nanometer resolution. Eleven distinct case materials are investigated for atomic features of their major alloying elements. Molecular features of case material combustion products are also investigated for five case materials. Emission is monitored within the 275–425 nm range for atomic features and in the 310–755 nm range for molecular features. Major alloying elements with concentrations greater than 5% are generally detected through atomic emission. Al, Cu, Fe, Mg, Cr, Mn, Pb, and Ni are all detected in concentrations less than 5%. Undetected elements include Zn, Nb, Ta, and V. Molecular emission from aluminum monoxide, titanium monoxide, and CN is measured for aluminum alloy, titanium alloy, and carbon fiber cases, respectively. Graphical Abstract [ABSTRACT FROM AUTHOR]

Thin sheets of N155 superalloy with Inconel 718 filler metal were welded using tungsten inert gas (TIG) process with different frequencies of the pulse current system. The present study aims to compare the hot corrosion resistance of the weld metal of samples with different frequencies in 90% Na2SO4-10% NaCl molten salt environment at 950±5 °C. The results of the hot corrosion test indicated that the sample with optimal frequency (240 Hz) could form the alternate protective layers (Cr2O3 and NiO) that prevented the interference of the iron element during the hot corrosion; therefore, the amount of damage to the substrate was reduced, and it made the parabolic rate constant (Kp) lower (up to 6h: 1.87 and after 6h: 0.186 (×10^(-10) g2.cm-4.s-1)) than other welded specimens. In other welded specimens, due to the formation of poor and rich areas of chromium and nickel key elements, resulting from elements segregation of welding solidification, the weld metal surface was not uniformly corroded and the iron element created porous and brittle Fe3O4 oxide layers. [ABSTRACT FROM AUTHOR]

Samples of ductile iron alloyed with 0.88 % Ni with a nodule count of 606, 523, and 290 nod/mm2 were obtained from sand cast plates of different thickness in the range from 8.46 to 25.4 mm. The effect of the nodule count was evaluated during the austempering process held at 285 °C and austempering times of 15, 30, 45, 60, 70, and 90 min. The volume fraction of high carbon austenite increased when the nodule count increased, however, the carbon content of the high carbon austenite kept almost constant. The process window was narrow, requiring a lower austempering time when the nodule count increased. The combination of a higher nodule count and low austempering temperature allowed obtaining a fine ausferritic microstructure which led to higher Brinell hardness and tensile strength. The process window was determined by XRD measurements and it was in good agreement with the microstructural and hardness evolution as the austempering time increased. [ABSTRACT FROM AUTHOR]

Conventional non‐rare‐earth permanent magnet (PM) electrical machine can hardly achieve comparable performance with the neodymium iron boron (NdFeB) machine due to the low coercivity and remanence. To solve this problem, a new kind of electrical machine using only Alnico magnet is proposed in this study. The novel rotor topology eliminates rotor iron core, and thus effectively limits armature reaction and improves torque density. A kind of rapid assessment method for the demagnetisation effect of q current in different slot–pole combinations through magnetomotive force and winding factor is presented and verified by 2D finite‐element analysis. The optimisation of critical dimensions is demonstrated, and the trade‐off between high PM utilisation and low demagnetisation effect is emphasised. After that, the good torque–current linearity and robust to demagnetisation characteristics of the proposed topology are proved through a comparison with two rare‐earth‐free machines. Finally, the performance comparison with a manufactured conventional NdFeB machine under the same volume constraints is provided. The result suggests that the proposed machine has a higher power factor, lower eddy‐current loss, and rare‐earth PM machine comparable torque density. [ABSTRACT FROM AUTHOR]

The recently discovered 12442-type iron-based superconductors (IBSs), ACa2Fe4As4F2 (A = K, Rb, Cs), are intrinsically self-hole doped stoichiometric compounds that exhibit superconductivity with Tc = 30–33.5 K. In this paper, single crystals of Ni doped RbCa2(Fe1−xNix)4As4F2 with 0 ⩽ x ⩽ 0.1 have been successfully grown for the first time using a RbAs flux method and characterized by energy dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD), electrical resistivity, magnetic susceptibility, and Hall effect measurements. EDS and XRD measurements suggest that the Ni dopants are successfully doped into the crystal lattice. Based on the electrical resistivity and magnetization data, we construct the Tc–x phase diagram. Furthermore, it is found that Ni dopants not only introduce extra electrons that modify the topology of Fermi surface, but also act as impurity scattering centers that contribute to the pair breaking effect, i.e., the superconducting transition temperature Tc is suppressed with a rate of ΔTc/Ni-1% = −2.7 K. Intriguingly, such suppression of Tc and those in other similar hole doped IBSs, such as Ba0.6K0.4Fe2As2, Ba0.5K0.5Fe2As2, and EuRbFe4As4 with multiple nodeless gaps, can be well scaled together. Combining with relevant experimental data reported so far, we speculate that the pairing symmetry in 12442 system is very likely to be nodeless s±-wave. Finally, doping evolution of the upper critical field and its anisotropy are investigated and discussed in detail. Upon Ni doping, the coherence length ξc(0) is gradually increased and becomes larger than the FeAs interbilayer distance when x > 0.07, indicating that the nature of superconductivity changes from quasi two-dimensional (2D) to three-dimensional (3D). The anisotropy of the upper critical field γH close to Tc shows a nonmonotonic dependence on doping, which first increases from 6.7 at the pristine sample to its maximum 8.1 at x = 0.03, and then decreases to 3.7 at x = 0.09. [ABSTRACT FROM AUTHOR]

The recently discovered 12442-type iron-based superconductors (IBSs), ACa2Fe4As4F2 (A = K, Rb, Cs), are intrinsically self-hole doped stoichiometric compounds that exhibit superconductivity with Tc = 30–33.5 K. In this paper, single crystals of Ni doped RbCa2(Fe1−xNix)4As4F2 with 0 ⩽ x ⩽ 0.1 have been successfully grown for the first time using a RbAs flux method and characterized by energy dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD), electrical resistivity, magnetic susceptibility, and Hall effect measurements. EDS and XRD measurements suggest that the Ni dopants are successfully doped into the crystal lattice. Based on the electrical resistivity and magnetization data, we construct the Tc–x phase diagram. Furthermore, it is found that Ni dopants not only introduce extra electrons that modify the topology of Fermi surface, but also act as impurity scattering centers that contribute to the pair breaking effect, i.e., the superconducting transition temperature Tc is suppressed with a rate of ΔTc/Ni-1% = −2.7 K. Intriguingly, such suppression of Tc and those in other similar hole doped IBSs, such as Ba0.6K0.4Fe2As2, Ba0.5K0.5Fe2As2, and EuRbFe4As4 with multiple nodeless gaps, can be well scaled together. Combining with relevant experimental data reported so far, we speculate that the pairing symmetry in 12442 system is very likely to be nodeless s±-wave. Finally, doping evolution of the upper critical field and its anisotropy are investigated and discussed in detail. Upon Ni doping, the coherence length ξc(0) is gradually increased and becomes larger than the FeAs interbilayer distance when x > 0.07, indicating that the nature of superconductivity changes from quasi two-dimensional (2D) to three-dimensional (3D). The anisotropy of the upper critical field γH close to Tc shows a nonmonotonic dependence on doping, which first increases from 6.7 at the pristine sample to its maximum 8.1 at x = 0.03, and then decreases to 3.7 at x = 0.09. [ABSTRACT FROM AUTHOR]

Most of the conventional linear generator is constructed with either Alnico (specially AlNiCo‐9) or Neodymium iron boron (NdFeB) permanent magnets (PMs) for harvesting oceanic wave energy. Alnico is a composition of aluminium (Al), nickel (Ni), and cobalt (Co) added to iron, which is its major volumetric component. Alnico has a poor magnetic energy product, and NdFeB contains a rare earth element. To overcome this issue, a recently developed rare‐earth free iron nitride (Fe16N2) compound‐based PM linear generator (PMLG) is proposed in this study as an alternative solution for avoiding rare earth material while obtaining high output power. To the best of authors' knowledge, newly invented Fe16N2 is not proposed, analysed, and investigated in any electrical generator. In this context, Fe16N2 is proposed in a linear generator as PM for producing adequate magnetic flux. For analysis and testing the performance of the proposed material, a PMLG is designed. The performances are compared for using Fe16N2 and AlNiCo PMs in the same PMLG design for a fair comparison. It is considered that the proposed PMLG is connected to a direct drive power take‐off system. Simulation results show that the proposed PMLG having Fe16N2 generates 55% more electrical power than that of using AlNiCo. The voltage, current, magnetic flux linkage, power, and magnetic flux density of the proposed PMLG are investigated extensively and compared with those of AlNiCo. The finite element method is applied in the ANSYS/Maxwell software environment for testing the PMLG with the conventional and the proposed PMs as well as results are presented. The proposed design is also validated with a small laboratory prototype. [ABSTRACT FROM AUTHOR]

The magnetoelectric (ME) characterization of stickup bilayers Ni0.8Zn0.2Fe2O3-Pb(Zr, Ti)O3 and trilayers of Ni0.8Zn0.2Fe2O3-Pb(Zr, Ti)O3-Ni0.8Zn0.2Fe2O3 are discussed. The ME interactions in the trilayers were found much stronger than that of bilayers prepared with the same technique. The maximum transverse ME voltage coefficient of trilayer can reach 430 (mV/cm Oe) under a magnetic field H=215 Oe. This value is much closer to the theoretical estimate for the ME coupling for bilayers. The frequency dependence of αE also reveals the difference of the elastic and magnetoelectric coupling between the bilayers and trilayers. Analysis suggests that a more approach linear response of the pezioelectric layer to the magnetostriction of the ferrite may be responsible for the significant enhanced ME effect in the trilayers. [ABSTRACT FROM AUTHOR]

The effect of strain rate on mechanical properties at room temperature (RT) and a cryogenic temperature (77 K) was studied in a nanocrystalline Ni–20%Fe alloy (grain size: 22 nm). The activation volume, strain rate sensitivity, strain hardening rate, and microstructural changes were also characterized. The results show that this nanocrystalline alloy has a combination of high strength and large plastic strain at both temperatures. At 77 K, the strength increased dramatically without a loss in the plasticity. Calculations demonstrate that the effect of temperature on yield strength, activation volume, and strain rate sensitivity is strongly dependent on the grain size. The high strain rate sensitivity and strong yield strength dependence on temperature are due to small activation volumes at fine grain sizes. In addition, at 77 K, both the activation volume and strain rate sensitivity exponent decreased significantly. The effect of temperature on the strain hardening capability in this nanograined alloy is opposite to what was observed for the large-grained metals. Comprehensive analysis suggests that the deformation at 20 nm is still dominated by dislocations. However, the dislocation generation models may be different at RT and 77 K. [ABSTRACT FROM AUTHOR]

Two sets of NiFe/FeMn films with Ta and Ta/Cu buffer layers were prepared by magnetron sputtering to study the influence of different buffers on the exchange coupling process. The results show that the exchange bias field (Hex) of NiFe/FeMn films with a Ta/Cu buffer is lower than that of films with a Ta buffer. There is no apparent difference in the texture and roughness of films both with Ta and Ta/Cu buffers. However, the segregation of Cu atoms on the surface of NiFe in the trilayer of Ta/Cu/NiFe was found by using angle-resolved x-ray photoelectron spectroscopy (XPS). A decrease of Hex for NiFe/FeMn films with a Ta/Cu buffer layer is primarily caused by the segregation of Cu atoms to the interface of the NiFe and FeMn layers. In order to suppress the Cu segregation, we deposited Bi insetting layers at the interface of Cu and NiFe in Ta/Cu/NiFe/FeMn/Ta films and found that Hex of NiFe/FeMn can be doubled when the proper quantity of Bi is deposited. XPS analysis shows that Bi insetting layers deposited at the interface of Cu and NiFe effectively suppress the Cu segregation on the NiFe layer. As a result, Hex is increased. However, if the insetting Bi is deposited excessively, it will partially migrate to the FeMn layer, damaging the antiferromagnetic property of the FeMn layer, thereby resulting in decreased Hex. When Ag and Pb were deposited at the interface of Cu and NiFe in Ta/Cu/NiFe/FeMn/Ta films, similar experimental results were obtained. [ABSTRACT FROM AUTHOR]