Alloy Ribbons Research Articles

Self-supported electrode Fe35Co20Ni20Mo20Si5 alloy ribbon: Electronic structure modulating oxygen evolution reaction

Non-precious metals as oxygen evolution reaction (OER) electrocatalysts for water-splitting purposes has recently attracted extensive attention. However, alloy ribbons of non-precious metals as self-supported electrodes for OER electrocatalysts have rarely been reported. Here we report a melt-spinning method to prepare an Fe35Co20Ni20Mo20Si5 alloy ribbon, which serves as a self-supporting electrode OER electrocatalysts by dealloyed etching. The etching expands the active surface area of the alloy ribbon which increases the abundant active sites. The experimental results showed that the electronic structure of FeMoSi on the ribbons surface excellently facilitates the OER process. The electrocatalytic activity test showed that the etched alloy ribbon exhibited excellent OER activity in 1 M KOH alkaline solution, with an overpotential of only 260 mV at a current density of 10 mA cm−2, a Tafel slope as low as 37.9 mV dec−1 and a stability of up to 90 h without decay. This work serves as a promising guide for the use of alloy ribbons as a highly efficient and self-supported electrocatalyst.

Magnetic softening of the Fe83Si3B11P2Cu1 amorphous/nanocrystalline alloys with large-size pre-existing α-Fe grains by high heating-rate annealing

The microstructure and soft magnetic properties of Fe83Si3B11P2Cu1 (at.%) nanocrystalline ribbons with different thicknesses up to 40 μm obtained by annealing the amorphous/nanocrystalline precursors at various heating rates (HRs) were studied. It was found that the thicker melt-spun alloy ribbons contain more and coarser α-Fe grains owing to the lower cooling rates during the solidification of melt spinning. By rapidly annealing the relatively thick amorphous/nanocrystalline precursors with the large-size pre-existing α-Fe grains at a high HR of about 100 °C/s, the resultant nanocrystalline alloys exhibit low coercivity (Hc) of about 5.2 A/m and high saturation magnetization (Bs) of about 1.83 T, which are approximate to the nanocrystalline alloys acquired by annealing the precursors with an amorphous structure. The strong competition among the formation of primary nuclei and the growth of the pre-existing and the newly-nucleated α-Fe induced by the more rapid annealing could effectively suppress the coarsening of the pre-existing α-Fe with the large size up to about 30 nm, which facilitates the formation of the fine and uniform nanostructure and magnetic softening of the resultant nanocrystalline alloys.

Change in Magnetic Anisotropy at the Surface and in the Bulk of FINEMET Induced by Swift Heavy Ion Irradiation.

57Fe transmission and conversion electron Mössbauer spectroscopy as well as XRD were used to study the effect of swift heavy ion irradiation on stress-annealed FINEMET samples with a composition of Fe73.5Si13.5Nb3B9Cu1. The XRD of the samples indicated changes neither in the crystal structure nor in the texture of irradiated ribbons as compared to those of non-irradiated ones. However, changes in the magnetic anisotropy both in the bulk as well as at the surface of the FINEMET alloy ribbons irradiated by 160 MeV 132Xe ions with a fluence of 1013 ion cm−2 were revealed via the decrease in relative areas of the second and fifth lines of the magnetic sextets in the corresponding Mössbauer spectra. The irradiation-induced change in the magnetic anisotropy in the bulk was found to be similar or somewhat higher than that at the surface. The results are discussed in terms of the defects produced by irradiation and corresponding changes in the orientation of spins depending on the direction of the stress generated around these defects.

Influence of partial substitution of Ti for Al on microstructure, thermal stability and corrosion resistance of novel quaternary Ni33.3Y33.3Al33.4-xTix medium entropy metallic glasses

In this present study, the influence of partial substitution of Ti for Al on microstructure, thermal stability and corrosion resistance of novel quaternary low-density Ni33.3Y33.3Al33.4-xTix (x = 3∼21 at.%) medium entropy metallic glass ribbons (ME-MG ribbons) was investigated. According to the rule of atomic radius similarity, by gradually replacing Al by Ti, we have synthesized a series of multi-component glassy alloy ribbons via using a single roller melt-spinning technique and also have examined their phase structure, thermal characteristics, microhardness and anti-corrosion properties. Besides, the phase composition of some representative annealed ribbon samples and the crystallization activation energy of these melt-spun ME-MG ribbons have been also determined and studied in detail. Results show that all of the rapidly solidified alloy ribbons can maintain completely amorphous nature. However, the thermal stability of ME-MG ribbons becomes reduced with the increasing Ti content. The maximum crystallization onset temperature at the heating rate of 20 K/min is around 706.65 K for Ni33.3Y33.3Al30.4Ti3 alloy ribbons. The maximum apparent activation energy of crystallization by means of thermodynamic analysis can be up to ∼803 kJ/mol for Ni33.3Y33.3Al21.4Ti12 alloy ribbons. The average microhardness value of these metallic ribbons can reach 455 HV0.1 or more when Ti content is less than 15 at.%, which is approximately 1.5 times the hardness of the Al-based amorphous alloy ribbons. The microstructural characterization of each ME-MG ribbon surface in as-received state and after a period of 45-hour and 75-hour corrosion immersion in 0.6 M NaCl solution was applied by scanning electron microscopy as well. Substituting moderately Al with Ti can effectively improve the anti-corrosion ability; the most positive pitting corrosion potential and the smallest corrosion current density are approximately -0.145 VSCE and 0.045 μA/cm2 for Ni33.3Y33.3Al24.4Ti9 and Ni33.3Y33.3Al27.4Ti6 ME-MG ribbons, respectively. Thus, it can be deduced that these new-fashioned ME-MG ribbons possess the superior anti-corrosion property, higher microhardness and acceptable thermal stability simultaneously, which may open momentous possibilities for the development and practical application of high-performance metal materials.

Tailored martensitic transformation and enhanced magnetocaloric effect in all-d-metal Ni35Co15Mn33Fe2Ti15 alloy ribbons

The crystal structure, martensitic transformation and magnetocaloric effect have been studied in all-d-metal Ni35Co15Mn33Fe2Ti15 alloy ribbons with different wheel speeds (15 m/s (S15), 30 m/s (S30), and 45 m/s (S45)). All three ribbons crystalize in B2-ordered structure at room temperature with crystal constants of 5.893(2) Å, 5.898(4) Å, and 5.898(6) Å, respectively. With the increase of wheel speed, the martensitic transformation temperature decreases from 230 K to 210 K, the Curie temperature increases slightly from 371 K to 378 K. At the same time, magnetic entropy change (ΔS m) is also enhanced, as well as refrigeration capacity (RC). The maximum ΔS m of 15.6(39.7) J/kg⋅K and RC of 85.5 (212.7) J/kg under ΔH = 20 (50) kOe (1 Oe = 79.5775 A⋅m−1) appear in S45. The results indicate that the ribbons could be the candidate for solid-state magnetic refrigeration materials.

Tunable nucleation process of nano-sized NaZn13-type and α-(Fe,Si) phases by doping boron in La–Fe–Si alloys during rapid solidification

The effect of a small dose of boron-doping on the nucleation process of nano-sized 1:13 phase (NaZn13-type phase) and α-(Fe,Si) phase of the La–Fe–Si alloys during the rapid solidification was investigated. The simulation of classical nucleation theory indicates a competitive nucleation relationship between 1:13 and α-(Fe,Si) phases during the rapid solidification. Compared to the La–Fe–Si alloys undoped with boron atom, the undercooled temperature change (ΔT) for the same nucleation rate conditions of the 1:13 and α-Fe phases was significantly decreased from 673 K (x = 0) to 639 K (x = 0.3) during the rapid solidification of La–Fe–Si–B alloys. The analysis of the microstructure and phase structure of the La–Fe–Si alloys ribbons by scanning electron microscope , x-ray diffraction, and transmission electron microscope also concludes that the doping of boron promoted the formation of the 1:13 phase. The results of this study have considerable meaning for the engineering application of magnetic refrigeration materials (La–Fe–Si) in the future.

Amorphous transformation of ternary Cu45Zr45Ag10 alloy under microgravity condition

The influences of undercooling rate and cooling rate on the microstructural evolution of ternary Cu45Zr45Ag10 alloy using single-roller melt spinning and drop tube are investigated. The rapidly quenched alloy ribbons achieve a homogeneous glass structure. The microstructure of the droplets transforms from the Cu10Zr7 dendrites plus (Cu10Zr7 + AgZr) eutectic into Cu10Zr7 dendrite with the decrease of droplet diameter. As the diameter decreases to 180 μm, the Cu45Zr45Ag10 alloy changes from crystal to amorphous structure, showing that the cooling rate is not the only influence factor and the undercooling play a certain role in the forming of the amorphous alloy at the same time under microgravity condition.

Effect of Ge Addition on Magnetic Properties and Crystallization Mechanism of FeSiBPNbCu Nanocrystalline Alloy with High Fe Content

In this work, new Ge-containing Fe-based nanocrystalline alloys with the composition of Fe80.2Si3B12-xP2Nb2Cu0.8Gex (x = 0, 1, 2 at.%) were developed, and the effects of Ge content on the magnetic and crystallization processes of the alloys were investigated. The addition of Ge extends the annealing window of the present Fe-based alloys, which reaches 173.6 K for the alloy of x = 2. The nanocrystalline alloy of x = 2, composed of dense and uniformly distributed α-Fe grains with an average grain size of 15.7 nm precipitated in the amorphous matrix, was obtained by conventional annealing treatment at a temperature of 843 K for 10 min, and this nanocrystalline alloy exhibited excellent magnetic properties with the Hc of 3 A/m and Bs of 1.65 T, which has great potential for industrial application. Non-isothermal crystallization kinetics studies show that the nucleation activation energy of the alloys gradually decreases with the increase in Ge content. The primary crystallization process is dominated by the direct growth of pre-existing nuclei in the as-spun alloy ribbons, and these pre-existing nuclei provide numerous heterogeneous nucleation sites to form dense and uniform α-Fe nanocrystals with a fine grain size, which leads to the excellent magnetic properties of the present Ge-containing Fe-based nanocrystalline alloys.

Preparation and Electromagnetic Absorption Properties of Fe73.2Si16.2B6.6Nb3Cu1 Nanocrystalline Powder.

In order to decrease and control electromagnetic pollution, absorbing materials with better electromagnetic wave absorption properties should be developed. In this paper, a nanocrystalline alloy ribbon with the composition of Fe73.2Si16.2B6.6Nb3Cu1 was designed and prepared. Nanocrystalline alloy powder was obtained by high-energy ball milling treatment. The effects of ball milling time on the soft magnetic properties, microstructure, morphology, and electromagnetic wave absorption properties of alloy powder were investigated. The results showed that, as time increased, α-(Fe, Si) gradually transformed into the amorphous phase, and the maximum saturation magnetization (Ms) reached 135.25 emu/g. The nanocrystalline alloy powder was flakelike, and the minimum average particle size of the powder reached 6.87 μm. The alloy powder obtained by ball milling for 12 h had the best electromagnetic absorption performance, and the minimum reflection loss RLmin at the frequency of 6.52 GHz reached −46.15 dB (matched thickness was 3.5 mm). As time increased, the best matched frequency moved to the high-frequency direction, and the best matched thickness decreased, while the maximum effective absorption bandwidth ΔfRL<−10 dB was 7.22 GHz (10.78–18 GHz).

Effects of P addition on the glass forming ability, crystallization behaviour and soft magnetic properties of FeNi-based amorphous alloy

In this work, the effects of P substitution on the thermal stability, crystallization behavior, and magnetic properties of melt-spun and annealed (Fe40Ni40Si9.5B9.5-xPxCu1)0.97Nb0.03 (x = 0, 1, 2, 3 and 4) alloy ribbons the have been explored. All alloys can be readily fabricated into completely amorphous structures with good surface quality by the melt-spinning method. Thermodynamic investigation reveals that proper P addition not only favors the amorphous formation but also enhance anti-crystallization ability. These alloys show excellent magnetic properties after optimal annealing, i.e., low coercivity (Hc) of 0.06–1.16 A/m, high permeability (μe) of 11680–17100 and moderate saturation magnetization (Ms) of 85.4–97.6 Am2/kg. Besides, the substitution of minor P metalloids facilitates homogeneous precipitation of α-Fe nanocrystals. This work helps us to develop a novel the FeNi-based alloy is vital important for achieving excellent soft magnetic properties.

Microstructure and properties of melt-spun AlYNiCr multi-component amorphous alloy ribbons through partial substitution of Cr for Ni

In this study, the effect of partial substitution of Cr for Ni on microstructure, thermal and anti-corrosion properties of Al33.3Y33.4Ni33.3−xCrx (x = 1 ∼ 10 at.%) multi-component amorphous alloy ribbons was investigated. The onset crystallization temperature of metallic ribbons are all above 720 K. The average micro-hardness of each specimen is over 510 HV0.1. In spite of partial substitution of Cr for Ni, the self-corrosion potentials are almost unchanged and the maximum of pitting corrosion potential can reach −0.51 VSCE for Al33.3Y33.4Ni27.3Cr6 alloy ribbons. When the Cr content increases from 1 at.% to 10 at.%, it can result in a decrease of corrosion current density from 6.46 × 10−5 A/cm2 of the Al33.3Y33.4Ni32.3Cr1 to 3.63 × 10−5 A/cm2 of the Al33.3Y33.4Ni31.3Cr2 and then increase to 4.67 × 10−4 A/cm2 of the Al33.3Y33.4Ni23.3Cr10 alloy ribbons. The minimum of passive current density can reach 1.05 × 10−4 A/cm2 for Al33.3Y33.4Ni29.3Cr4 alloy ribbons. Therefore, it is assumed that substituting appropriate content of Ni by Cr element into equimolar AlNiY medium entropy amorphous alloys can improve the ability to resist pitting corrosion in 3.5 wt% NaCl solution.

Magnetic Properties and Microstructural Modifications of Sm-Co-Hf Alloy Ribbons by B Addition

Magnetic Properties and Microstructural Modifications of Sm-Co-Hf Alloy Ribbons by B Addition

Crystallization and hydrogen absorption in a Ni32Nb28Zr30Fe10 melt spun alloy and correlation with icosahedral clusters

The crystallization and the hydrogen absorption properties of a Ni 32 Nb 28 Zr 30 Fe 10 melt spun ribbon were investigated. X-ray diffraction measurements reveal that a small fraction of the ribbon is in a crystalline state, whereas the main component is amorphous. The bulk crystallization process of the alloy ribbon occurs in two steps above 770 K, as measured by differential scanning calorimetry. At each step of the crystallization process, an unusually low activation energy of the order of 180 kJ/mol, was observed. Hydrogen absorption pressure-composition isotherms measured between 598 K and 673 K showed that the enthalpy of hydrogenation is quite high (∼85 kJ/mol), as compared to that of analogous ribbons. The isotherms of these ribbons do not exhibit any plateau, similarly to other amorphous materials, but they exhibited extremely slow kinetics for hydrogen absorption. To simulate the local atomic structure involving cluster formation in amorphous Ni 32 Nb 28 Zr 30 Fe 10 alloy, DFT-MD approach was used to construct an amorphous supercell of this alloy with 108 atoms. Calculations predicted that a fully amorphous structure of Ni 32 Nb 28 Zr 30 Fe 10 can form. The low activation energy of crystallization observed before hydrogenation is due to the presence of only 3 full icosahedra without any Ni-centered icosahedra, that could provide resistance against crystallization. Moreover, a cluster analysis of the Ni 32 Nb 28 Zr 30 Fe 10 alloy after hydrogenation showed interaction of hydrogen atoms with only two icosahedra out of four found in this case, and this could be the probable reason for the extremely slow kinetics of hydrogen absorption. • Melt spun Ni 32 Nb 28 Zr 30 Fe 10 is mainly amorphous with a minor crystalline inclusion. • Activation energy for crystallization is extremely low (180 kJ/mol). • Large quantities of hydrogen are stored with a slow kinetics. • DFT Molecular Dynamics show the alloy has poor resistance to crystallization. • Hydrogen interacts with two out of four icosahedral clusters with a slow kinetics.

Reducing the Core Losses of Fe-Si-B Amorphous Alloy Ribbons by High Cooling Rate Planar Flow Casting.

In the planar flow casting (PFC) process, the cooling rate significantly affects the structure and properties of a cast ribbon. The influence of the thermal conductivity of the cooling wheel substrate on cooling rate was simulated by a numerical method, and it is shown that a higher thermal conductivity of the cooling wheel substrate leads to a higher cooling rate in the PFC process. Two copper-beryllium (Cu-2Be) rings with thermal conductivities of 175.3 W/m·K and 206.5 W/m·K were manufactured and installed onto a wheel core as the substrate of the cooling wheel. The effects of cooling rate on the soft magnetic properties of Fe-Si-B amorphous ribbons were investigated by pragmatic ribbon casting. The results show that the increment in the thermal conductivity of the cooling wheel substrate from 175.3 W/m·K to 206.5 W/m·K lowered the coercive force of amorphous ribbon from 2.48 A/m to 1.92 A/m and reduced the core losses at 1.4 T and 50 Hz by up to 22.1%.

Microstructures and soft magnetic properties of Fe73.5-xCu1Nb3Si13.5B9Yx (x = 0–1.5) alloys

Adding Y to replace Fe in composition of Finemet alloy, and prepare alloy samples of Fe73.5-xCu1Nb3Si13.5B9Yx (x = 0, 0.5, 1.0, 1.5) to study the structures and soft magnetic properties. After vacuum melting and rapid cooling, the rapidly solidified as-cast alloy ribbons were prepared, and Fe73.5-xCu1Nb3Si13.5B9Yx (x = 0, 0.5, 1.0) as-cast samples have single phase of amorphous structure. So the alloys are amorphous by rapid cooling within the addition of Y less than 1.0%. After annealing, nanocrystalline appeared in the matrix, the nanocrystals are randomly oriented and the grain size of Fe73Cu1Nb3Si13.5B9Y0.5 alloy is around 10 nm, the ordered crystal planes can be observed, it is consistent with α-Fe(Si). From the APT we can see the distribution of elements, Fe and Si are mostly in the grain, Nb and B are in the grain boundary and amorphous phase, and Cu is in clusters. The Fe73Cu1Nb3Si13.5B9Y0.5 alloy has the best soft magnetic properties, with the μi and μm values ​​are 149.93 k and 1213.00 k, respectively, which are 22.19% and 43.72% higher than Finemet. The Fe73Cu1Nb3Si13.5B9Y0.5 alloy also has excellent soft magnetic properties at high temperature, when the ambient temperature at 120 °C and 150 °C, the μe values increased by 42.21% and 40.95% than Finemet at 1 k Hz, respectively; and increased by 14.30% and 19.70% at 10 k Hz. In addition, the Fe72.5Cu1Nb3Si13.5B9Y1 alloy has the lowest coercivity value of 0.40 A/m.

Optimization of crystallization, microstructure and soft magnetic properties of (Fe0.83B0.11Si0.02P0.03C0.01)99.5Cu0.5 alloy by rapid annealing

A (Fe0.83B0.11Si0.02P0.03C0.01)99.5Cu0.5 glass former was formulated based on Fe83B11Si2P3C1 alloy and a new rapid annealing method was employed to investigate both the temperature and time effect on the improvement of soft magnetic properties of the amorphous alloy ribbon. The results show that the interval between the first and second crystallization temperature is enlarged by Cu addition. There exists an optimal annealing time corresponding to the optimal Bs and Hc for the ribbon annealed at each temperature. The maximum Bs up to 1.74 T and the minimum Hc of 4.9 A/m were obtained for the ribbon annealed at 426 °C for 150 s. The grain number density of precipitated α-Fe(Si) is the main factor in determining the Bs. Compared to other nanocrystalline alloys with similar Fe content, the present alloy ribbon annealed by the new method shows a higher Bs and a lowest Hc, which makes it a promising soft magnetic material used in the field of electrical and electronic industries.

Regulation mechanism of giant magneto-impedance effect of multi-field coupling Fe-based alloy

Fe-based amorphous and nanocrystalline alloys are considered as the preferred dual-green energy-saving materials due to their unique magnetic properties, such as high permeability, low coercivity, and near-zero saturation magnetostriction. As such, they have received extensive attention in applications like magnetic core material for high-frequency transformers, common model chokes, ground fault interrupters, and rotors in motors, over the past decades. In this work, Fe&lt;sub&gt;64.8&lt;/sub&gt;Co&lt;sub&gt;7.2&lt;/sub&gt;Nb&lt;sub&gt;4&lt;/sub&gt;Si&lt;sub&gt;4.8&lt;/sub&gt;B&lt;sub&gt;19.2&lt;/sub&gt; (in atom percent) amorphous alloy ribbons are prepared by using the single roller quenching method, then subsequently subjected to multi-field coupling heating treatment in the air which includes heating by Joule heating effect and tensile stress field. Furthermore, the longitudinally driven giant magneto-impedance effect and magnetic domain structures of ribbons are observed by using 4294A impedance analyzer and magnetic force microscopy, respectively. The magneto-crystalline anisotropy field and stress anisotropy field of ribbons are analyzed by using X-ray diffraction, random anisotropy model, and numerical fitting. Meanwhile, the concept of magnetic anisotropy competing factor (&lt;i&gt;k&lt;/i&gt;) is proposed, from the viewpoint of magnetic anisotropy, a mechanism for regulating giant magneto-impedance effect of ribbons prepared with multi-field coupling is studied. It is found that the longitudinally driven giant magneto-impedance effect gradually transforms from the single peak to dome-like with tensile stress increasing. However, a spike and dome-like giant magneto-impedance effect appears during such transformation, which is composed of two parts: spike-like top and dome-like base. Based on the magnetic domain structure of ribbons, it is found that the typical stress-annealed transversal magnetic domain structure is observed in ribbons of &lt;inline-formula&gt;&lt;tex-math id="Z-20221115160531"&gt;\begin{document}$k \leqslant 0.147$\end{document}&lt;/tex-math&gt;&lt;alternatives&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="23-20221376_Z-20221115160531.jpg"/&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="23-20221376_Z-20221115160531.png"/&gt;&lt;/alternatives&gt;&lt;/inline-formula&gt;, while nucleation and splitting phenomenon of new domains are observed at the transversal magnetic domain wall in ribbons of &lt;i&gt;k&lt;/i&gt; &gt; 0.147. Both longitudinally driven giant magneto-impedance effect and domain structures provide evidence to support the competing inhibition effect of magnetic anisotropy which exists in Fe-based alloy ribbon. Therefore, it is suggested that Fe-based alloys exhibit excellent stress-sensitive properties that can be understood by the competing inhibition effects of magnetic anisotropy. It is further shown that the competing inhibition effect of magnetic anisotropy is the main reason for regulating the giant magneto-impedance effect of soft magnetic materials. This multi-field coupling Fe-based alloy has good application prospects in regulating magnetic properties of magnetic materials.

Mechanism of stress induced irreversible magnetic anisotropy in Fe-based alloy ribbons

Fe-based amorphous and nanocrystalline soft magnetic alloys are regarded as the significant dual-green energy-saving materials because of their superior magnetic properties and straightforward fabrication procedure. As such, they have attracted much attention in the fields of the electronic information and electrical power. In this work, Fe&lt;sub&gt;73.5&lt;/sub&gt;Cu&lt;sub&gt;1&lt;/sub&gt;Nb&lt;sub&gt;3&lt;/sub&gt;Si&lt;sub&gt;13.5&lt;/sub&gt;B&lt;sub&gt;9&lt;/sub&gt; (%) amorphous alloy ribbon is subjected to various physical ageing treatments in nitrogen atmosphere. These treatments include annealing at 540 ℃ for 30 min under different tensile stresses and isothermal tempering without tensile stress for several cycles. The origin of stress-induced magnetic anisotropy is investigated through using dynamic strain analysis, the longitudinally driven giant magento-impedance effect, and synchrotron radiation X-ray diffraction. In the process of tensile stress annealing, it is found that the axial strain of ribbon is elastic strain when annealing temperature is below the glass transition point, and plastic strain when annealing temperature is above the glass transition point; the precipitation of nanocrystalline phase has a pinning effect on amorphous matrix, which slows down the strain rates and makes the tend stable. Additionally, isothermal tempering studies show that the stress-induced magnetic anisotropy and lattice plane anisotropy have different relaxation patterns. It is found through numerical fitting that the stress-induced magnetic anisotropy can reach a stable value of 0.144 by infinite tempering, whereas the lattice plane anisotropy can only relax to zero by finite tempering. A model of nanocrystalline grain distribution anisotropy is developed to re-examine the origin of stress-induced magnetic anisotropy. It supports a viewpoint that the nanocrystalline grain distribution anisotropy &lt;inline-formula&gt;&lt;tex-math id="M4"&gt;\begin{document}$\Delta \delta $\end{document}&lt;/tex-math&gt;&lt;alternatives&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20221509_M4.jpg"/&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20221509_M4.png"/&gt;&lt;/alternatives&gt;&lt;/inline-formula&gt; is responsible for the stress-induced irreversible magnetic anisotropy &lt;inline-formula&gt;&lt;tex-math id="M5"&gt;\begin{document}${K_{\text{d}}}$\end{document}&lt;/tex-math&gt;&lt;alternatives&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20221509_M5.jpg"/&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20221509_M5.png"/&gt;&lt;/alternatives&gt;&lt;/inline-formula&gt;, and that their relationship can be described as a following function: &lt;inline-formula&gt;&lt;tex-math id="M6"&gt;\begin{document}${K_{\text{d}}} = k\Delta \delta $\end{document}&lt;/tex-math&gt;&lt;alternatives&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20221509_M6.jpg"/&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20221509_M6.png"/&gt;&lt;/alternatives&gt;&lt;/inline-formula&gt;. Therefore, it is proposed that the stress-induced anisotropy originates from a synergistic interaction between the lattice plane anisotropy and the nanocrystalline grain distribution anisotropy in Fe-based alloy ribbon. This work has important implications for understanding the mechanism of the stress-induced magnetic anisotropy.

Воздействие ионного облучения (Аr+, E = 15-20 кэВ) на микроструктуру деформированного сплава Ni - 13.9 мас.% W

Using X-ray diffraction analysis, the effect of Ar+ ions with an energy of 15-20 keV (at ion current densities of 100-300 μA/cm2) on the microstructure, the level of internal microstresses and the texture of cold rolled ribbons of alloy Ni-13.9 wt.% W was studied. It was found that short-term irradiation of 80 μm thick ribbons with a fluence of 3.1·1016 cm-2 (for 50 s) at temperatures T ≤ 370°C and T = 630°C leads to a decrease in microstresses in their entire volume, but at the same time the original texture is retained. With an increase in the fluence to 9.7·1017 cm-2 at T = 630°C, the texture also changes from (220) to (200). Changes in microstresses and texture on the irradiated and unirradiated sides of 80-μm-thick ribbons are comparable to each other, despite the fact that the projective range of Ar+ ions with an energy of 15-20 keV in the alloy is only ~7 nm. It is known that annealing in an oven (700°C, 30 min) of such ribbons does not lead to their recrystallization. At 850°C, microstresses are relieved and the texture drastically changed from (220) to (200) both as a result of annealing in a furnace (15 s) and as a result of irradiation with a fluence of 3.2·1016 cm-2 for 17 s, but the effect removal of stresses in the course of furnace annealing is 3 times lower than in the course of irradiation. Thus, the following facts have been established: 1) the occurrence of recrystallization processes in the alloy under study during irradiation at a temperature lower than the temperature of the onset of thermally activated recrystallization and 2) a higher rate of microstresses drop (and to lower values) in the course of irradiation than during furnace annealing. This indicates a significant role of nanoscale radiation-dynamic effects at the cascade-forming irradiation of metastable media.

Structure and Magnetic Properties of Ni50-Xcoxmn50-Yaly (X = 5 - 9, Y = 18 - 19) Shape Memory Alloy Ribbons

Structure and Magnetic Properties of Ni50-Xcoxmn50-Yaly (X = 5 - 9, Y = 18 - 19) Shape Memory Alloy Ribbons