Structural Heterogeneity of an Amorphous-Nanocrystalline Alloy Fe77Cu1Si16B6 in the Nanometer Range

In this article, an alloy of the Finemet type Fe77Cu1Si16B6 obtained by quenching from a liquid state (spinning method) in the initial state is investigated. The main research methods were scanning and transmission electron microscopy. Methods for describing multiscale structural heterogeneities in amorphous-nanocrystalline alloys have been developed, allowing the structural state to be described and its influence on the physicochemical and technical properties to be determined depending on the technological conditions for obtaining these alloys. Representation of electron microscopic images in the form of Fourier spectra made it possible to reveal the nature of the formation of short- and middle-order in amorphous-nanocrystalline alloys according to the principle of self-similar spatial structures. The analysis of electron microscopic images by integral Lebesgue measures revealed density fluctuations over the alloy volume, which corresponds to the hierarchical representation of structural inhomogeneities in amorphous metallic alloys.

Effect of Annealing on the Magnetic Properties of FeCoNiCuNbSiB Soft Magnetic Alloys

A series of nanocrystalline soft magnetic alloys with nominal compositions of Fe66.8-xCo10NixCu0.8Nb2.9Si11.5B8 (x = 1–15 at%) were developed and studied. Effects of annealing on the soft magnetic properties, crystallization behavior, and domain structure were investigated. The alloys with higher Ni content were prone to exhibit stronger magnetic anisotropy. The Fe66.8Co10Ni10Cu0.8Nb2.9Si11.5B8 alloy exhibited excellent soft magnetic properties, including the low permeability of 2000, low coercivity of about 0.6 A/m, and low remanence of 2.4 mT, together with a temperature gap of 128 K between two crystallization onset temperatures. It has been found that the Ni content and the annealing process possess significant effects on the soft magnetic property of the nanocrystalline alloys. It shows that the developed Fe66.8Co10Ni10Cu0.8Nb2.9Si11.5B8 nanocrystalline alloy exhibits great potentials for applying in the field of common mode chokes or current transformers, due to its ability to resist the direct current.

First-principles calculations of magnetic and mechanical properties of Fe-based nanocrystalline alloy Fe80Si10Nb6B2Cu2

Based on the first-principles calculation method of density functional theory (DFT), the crystal structure, band structure, magnetic moment, density of state, elastic constant and population analysis of Fe80Si10Nb6B2Cu2 are calculated. The calculation results show that the Fe-based nanocrystalline alloy of this composition has a stable structure, strong resistance to deformation, high hardness and is an alloy with good flexibility. The energy band structure of spin-up and spin-down is basically the same, and the energy gap is 0 eV, showing metallicity. The asymmetry of the electronic state density between the spin-up and spin-down states indicates that the alloy is ferromagnetic, with a magnetic moment of 84.15 μ; the Fe element plays a decisive role in the magnetic properties of this alloy.

Study on Properties and Heat Treatment Process of Fe75.9Cu1Si13B8Nb1.5Mo0.5Dy0.1

The soft magnetic properties of Fe[Formula: see text]Cu1Si[Formula: see text]B8Nb[Formula: see text]Mo[Formula: see text]Dy[Formula: see text] nanocrystalline alloy were studied which is designed on the basis of the Finemet type alloys. The X-ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), electric inductance measuring-testing instrument and MATS soft magnetic material AC/DC tester were used to study the effects of the effective permeability ([Formula: see text], saturation magnetic induction ([Formula: see text]), coercivity ([Formula: see text]), and hysteresis losses ([Formula: see text]) at 100[Formula: see text]kHz and 0.2[Formula: see text]T under factors such as different annealing temperatures, different thicknesses, and whether there is a need for transverse field for annealing. The results show that the commercial amorphous alloy ribbons Fe[Formula: see text] Cu1Si[Formula: see text]B8Nb[Formula: see text]Mo[Formula: see text]Dy[Formula: see text] have complete amorphous structure in as-cast state, and [Formula: see text]-Fe nanocrystalline phase precipitates on the amorphous matrix after vacuum annealing. Fe[Formula: see text] Cu1Si[Formula: see text]B8Nb[Formula: see text]Mo[Formula: see text]Dy[Formula: see text] alloy has high [Formula: see text] value and good thermal stability, which can better control the formation of nanocrystalline structure. The transverse magnetic field annealing can greatly increase the [Formula: see text] of the material and reduce the [Formula: see text], which is more significant for the ribbons. The optimum annealing process of Fe[Formula: see text]Cu1Si[Formula: see text]B8Nb[Formula: see text]Mo[Formula: see text]Dy[Formula: see text] alloy is that the transverse magnetic field of 1000[Formula: see text]Gs is applied and the temperature is kept at 833[Formula: see text]k for 30[Formula: see text]min. And the best properties for [Formula: see text] are 1.39[Formula: see text]T, for [Formula: see text] is 4.6[Formula: see text]A/m and [Formula: see text]@1[Formula: see text]kHz, [Formula: see text]@100[Formula: see text]kHz. With the high frequency and miniaturization of electronic components, this material has potential application value.