Fibers are fabricated from a Co69Fe4Cr4Si12B11 alloy glass covered amorphous microwire. They have two types of sizes: the diameter is D = 17 and 50 μm and the length is 7 and 15 mm, respectively. The influence of their geometric parameters and concentration (0.5–3

The direct current (dc) heating effect of ferromagnetic amorphous wires (AW) on the electromagnetic properties of the serial Co-based alloy, Co – Fe – Cr – Si – B, is investigated. The Ulitovsky – Taylor method was used to produce AW with diameters D = 40, 70, 82, 98, 123, and 145 μm in a glass shell, that was removed mechanically by elastic bending on a laboratory bench. The developed in situ method of stepwise cyclic dc heating of AW of various diameters enables to choose the optimal values of the current (Ia) for carrying out the selected modes that maximize the magnetic properties. AW electromagnetic properties were monitored by registering the amplitude of the intrinsic electromagnetic signal of electromotive force (EMF) of the AW sample under study. Since reliable direct measurements of AW temperature (Ta) when passing the current (Ia) quite an undertakings, we used indirect method of AW heating temperature estimation by establishing the relationship Ta = f (Ia). For the AW specified diameters, the direct current values were experimentally determined, which ensure optimal heat treatment in the range of temperature stability of the amorphous phase, up to the crystallization temperature, Tx. A calibration curve was constructed using reference temperature points, i.e. Tx and the Curie temperature (Tc). The proposed technique for calibration graph construction I = f(D) may be used for different AWs that have different diameters and same composition; it allows one to determine the modes of current annealing required for the best EMF amplitude values of amorphous wires of the given diameter, up to 100 μm.

The fiber was made from an amorphous microwire of the Co69Fe4Cr4Si12B11 alloy in a glass shell of two sizes: diameter D = 17 and 50 μm, length is 7 and 15 mm, respectively. The influence of its geometric parameters, concentration (0.5—3%) and method of introduction on mobility, average density, bending strength and compression of cement systems (solutions) have been studied. The 54% increase in the flexural strength of the cement system was established in the case of its reinforcement with amorphous glass-metal fiber with D = 17 μm in an amount of 0.5% by weight of Portland cement and 22% one in the case of reinforcement with fiber with D = 50 μm in an amount of 1%. In this case, the compressive strength changes slightly. The introduction of fiber increases the crack resistance coefficient of the studied cement systems from 0.098 to 0.116—0.164.

Structural analysis methods (metallographic, X-ray diffraction, differential scanning microscopy) were used to complex research of the structure Al82Cu7Fe11 alloy obtained melt spinning method in the form of ribbons. It was shown that a multiphase amorphous-nanocrystalline structure of high dispersity, which includes an aluminum-based solid solution, intermetallic compounds Fe4Al13, CuAl2, and a small amount of a quasi-crystalline Al – Fe – Cu phase with a tenth-order symmetry axis (decagonal) is formed in the alloy. The parameters of the crystal lattices and volume fractions of the phases were certified. Was shown that the main structural component alloy is iron aluminide, the which content varies from 68 wt. % to 61 wt.% over the ribbon cross section from the contact to the free surface. The temperatures of phase transformations in the alloy during heating were determined. A comparative analysis of the structure composition and morphology of the phases formed in rapidly quenched ribbons and crystallized under equilibrium conditions same composition ingot was carried out. The difference in the alloys structure after various methods of crystallization was established. The microhardness of the ingot main structural components has been determined. Iron aluminide has a maximum hardness 780 HV. It was shown that the high alloy hardness 615 HV after high-speed quenching is provided formed multiphase amorphous-nanocrystalline structure state.

Peculiarities of the fabrication and the physicomechanical properties of amorphous microwires and microspirals made from iron- and cobalt-based alloys, which determine advantages of these materials over available materials, are analyzed. Perspectives in their application in medicine and microelectronics and as parts and elements for promising technique are considered.

X-ray diffraction and differential thermal analyses are used to study multicomponent Nd–R–Fe–B (R = Pr, Ce, La) alloys prepared by induction melting in an inert gas atmosphere and subsequent forced cooling upon casting in a massive cast iron mold. The effect of substitution of light rare-earth metals for neodymium on the phase composition and morphology of the cast alloys with 0–6.9 wt % Pr, 0–10.0 wt % Ce, and 0–9.0 wt % La, which are used as precursors in manufacturing sintered permanent magnets with high hysteretic characteristics, is studied. The main structural constituents of the alloys are shown to be a magnetic phase with the Nd2Fe14B-type structure and Nd-rich, R1.1Fe4B4, and R2Fe17 phases. The phase transformation temperatures of the alloys are determined, which allow us to correct the sintering temperatures of permanent magnet powder blanks prepared from the cerium- and lanthanum-containing alloys.

The peculiarities of the gas release during melt solidification of cobalt alloy amorphous wires 50–80 μm in diameter, which are prepared by the Ulitovskii–Taylor, are considered. The results are compared with the pore-formation mechanism that takes place during the solidification of ingots fabricated by different technologies. The number of low-strength areas in a long amorphous wire, which are caused by local gas porosity, can be decreased using melt refining vacuum technologies.

The peculiarities of production and the physical-mechanical properties of amorphous microwires and microcoils made of alloys based on iron and cobalt, which determine advantages of such materials as compared with existing analogs, have been analyzed. The prospects of their application in medicine, microelectronics, as products and elements of promising technology are considered.

A study is performed of the effect intense laser heating has on the strength characteristics of the γ‑phase in iron–chromium–nickel alloys. We show that using laser radiation to heat the initial α-phase to the temperature of the α → γ transformation produces a γ-phase with much higher microhardness and yield stress than those of the equilibrium γ-phase. A possible mechanism of this phenomenon is discussed.

The mechanical properties of the wires made from the Co 69 Fe 4 Cr 4 Si 12 B 11 amorphous alloy, tungsten, molybdenum, and 40KKhNM steel and the microspirals made from the wires and the electromagnetic and tribological properties of the amorphous alloy wires, which are prepared with protective sheaths made in the form of a microspiral from the selected materials, are studied. All the wires are found to have a high tensile strength (2100–3100 MPa). Elastic compression ability of the microspirals is found. The friction is shown to be minimal in the amorphous alloy–amorphous spiral pair. As for a combination of the properties, an amorphous spiral containing a stress-sensitive amorphous wire can be recommended as a working element of an electromagnetic transducer.

The existing methods for obtaining amorphous wires of large diameters from a melt are considered. The advantages of the Ulitovsky–Taylor method for obtaining amorphous wires in a wide range of diameters with stable geometric characteristics are underlined. The factors that affect the process of obtaining “thick” amorphous wires by a continuous version of the Ulitovsky–Taylor method are analyzed. It is demonstrated why it is necessary to use alloys with a high glass-forming ability and with melting temperatures of 950–1150°C. The practicability of introducing technological additives (Nb, Mo, Cr, etc.) is justified. It is noted that, to ensure a continuous process of producing a “thick” wire, it is necessary to use a high-purity precursor with stable geometric parameters. A variant of a quenching device is proposed for cooling a melt jet with a counterflow of water. The technique for removing the glass cover is based on elastic bending of the metal core and brittle cracking of glass. The technology for producing “thick” wires was tested. Long wires with diameter of 50–200 μm with a high set of properties were manufactured.

The effect of the wire diameter and tensile and torsion loads on the remagnetization ability and the stress sensitivity of amorphous Co-alloy wires is investigated. It is shown that amorphous wires have a high magnetic softness to the applied external field in a wide range of diameters of 20–300 μm. The amplitude of the electromagnetic signal of electromotive force (EMF) increases with increasing wire diameter. It is established that amorphous wires with diameter in the range of 50–140 μm are sensitive to applied elastic tensile stresses. Increase in stresses to 300 MPa is accompanied by a fourfold decrease in the amplitude of the EMF signal. These wires are also sensitive to torsion stresses in a weakly and strongly stretched state. The first stage is accompanied by an intense increase in the amplitude of the EMF signal to values near to the amplitude of the original unloaded wire. At the second stage, the amplitude value achieved is preserved. It is established that an optimum interval of recording torsion stresses is determined by the wire diameter and values of applied tensile load. It is concluded that amorphous wires in a wide range of diameters can be used as highly sensitive noncontact sensors of field and tensile and torsion load detectors.

Abstract—The bending-deformation behavior of rapidly quenched Co69Fe4Cr4Si12B11 alloy wires 0.1–1 mm in diameter, which are fabricated by the Ulitovskii–Taylor method, are studied. A correlation between the failure mechanism of a wire and its diameter and bending loading conditions is shown. It is found that wires up to 0.2 mm in diameter exhibit no bending failure. The wedge-type fracture is observed for wires 0.2–0.35 mm in diameter; wires more that 0.35 mm in diameter exhibit steplike fracture. The wedge-type fracture, a dense regular shear-band network, and vein- and corallike fracture are shown to correspond to the 100% amorphous state of wires. This combination of signs is observed for wires up to 0.4 mm in diameter.

Results are presented from investigating the structural and magnetic characteristics of Co 69 Fe 4 Cr 4 Si 12 B 11 amorphous microwires with magnetic core diameters of 35–360 µm, obtained using an updated Ulitovskii–Taylor approach. It is found that the microwires have stable geometric dimensions along their lengths and almost defect-free surfaces. They are characterized by high plasticity and strength, and their magnetic characteristics depend on their diameter. The possibility of the microwires’ practical application is shown.

The mechanism of formation and propagation of shear bands on the surface of a model Co 69 Fe 4 Cr 4 Si 12 B 11 alloy amorphous wire 90 μm in diameter without a glass cover, which was subjected to different types of loading, such as uniaxial tension, drawing, bending, and torsion, is studied. For all applied loadings, the wire exhibits the ability to forming at a retained amorphous state. Depending on the type of loading, deformation is distributed either uniformly along the wire or is localized in a stress concentration zone. In this case, the contributions of forming mechanisms, namely, elastic deformation, ductile flow in the volume, and formation of shear bands on the wire surface, change. The wire is concluded to exhibit the pseudoplasticity effect.