Controlled nanostructuring from an amorphous state in multicomponental alloys based on cobalt

Lysov, V. I.; Tsaregradskaya, T. L.; Kurylyuk, A. M.; Turkov, O. V.; Saenko, G. V.

doi:10.30970/jps.22.3702

Cited by 3 publications

(9 citation statements)

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“…The onset point of the first peaks specifies the crystallization onset temperature of the alloys indicating the start of the nanocrystallization process as well as the temperature limit of amorphous phase stability. For Co-Fe-Ni-Si-B alloys, the temperature range of amorphous phase stability is in the range of about 750-850 K and depends on impurities and the production process [13,14,15].…”

Section: Resultsmentioning

confidence: 99%

“…It is known some amorphous-nanocrystalline alloys have physical properties that that are better than the properties of both amorphous and nanocrystalline materials. For example, their magnetic properties are better than the magnetic properties of amorphous ferromagnetic alloys and they have high strength, much higher than the strength of amorphous or crystalline states [20]. The grain size of the nanocrystalline structure of the alloy is determined by the crystallization mechanisms associated with the chemical composition and thermodynamic characteristicsе.…”

Section: Resultsmentioning

confidence: 99%

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Magnetic properties and nanocrystallization behavior of Co-based amorphous alloy

Nykyruy

Mudry

Kulyk

et al. 2023

Phys. Chem. Solid St.

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The magnetic properties of the amorphous Co57Fe5Ni10Si11B17 alloy have been studied by a vibrating sample magnetometer. The temperature dependence of saturation magnetization was measured and the Curie point and crystallization onset temperature were determined as 560 K and 760 K respectively. The coercive force was obtained as 200 A/m and saturation magnetization - 65 Am2 /kg. The alloy was produced in the form of a ribbon thickness of 30 µm using the melt spinning method, and its internal amorphous structure was examined by the X-ray diffraction method. The crystallization behavior of the alloy was studied using series of isothermal annealing of the samples of the alloy at temperatures in the range of 723-1023 K for different exposures (up to 240 minutes) and nanocrystalline phases were detected by the X-ray diffraction analysis.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Magnetic properties and nanocrystallization behavior of Co-based amorphous alloy

Nykyruy

Mudry

Kulyk

et al. 2023

Phys. Chem. Solid St.

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“…The main parameter that determines the crystallization kinetics of binary alloys is the concentration dependences of the Gibbs free energies of the amorphous and crystalline phases that arise in the process of phase formation. The relative integral Gibbs free energy of the amorphous phase is described by the following expression [4]:…”

Section: Equation For the Description Of The Crystalization Kinetics mentioning

confidence: 99%

“…0 is the modulus of this value at the extremum point. These parameters are determined from experimental and calculated data [4][5][6]. Fig.…”

Section: Equation For the Description Of The Crystalization Kinetics mentioning

confidence: 99%

“…Parameters of the concentration dependences of the relative integral Gibbs free energy of the amorphous phase in the Fe-Zr system were obtained based on the analysis of the state diagram and experimental data [4][5][6] and were chosen as:  H = 0.35,  H = -28.8•10 3 , a H = -235.1•10 3 , b H = 2.448,  V/V 0 = 0.15,…”

Section: Equation For the Description Of The Crystalization Kinetics mentioning

confidence: 99%

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Initiation of the Explosive Crystallization Process in Amorphous Alloys of the Fe-Zr System by Pulse Laser Treatment

Tsaregradskaya¹,

St.²,

Kunitskyi³

et al. 2019

J. Nano- Electron. Phys.

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In the work, a series of theoretical calculations were carried out to analyze the possibility of the process of explosive crystallization during laser treatment of binary amorphous alloys of the Fe-Zr system. The calculations were carried out within the framework of the modified theory of homogeneous crystallization for binary alloys, which takes into account the work associated with the concentration fluctuation. Calculation of the characteristics of the crystallization process was performed for two modes: slow heating at a speed of 0.16 K/s and an instant laser pulse, while it was considered that the amorphous tape was heated by a laser beam to a certain temperature within 10-6 seconds. The integral curve of the temperature dependence of the volume part of the crystalline phase during slow isothermal annealings is characterized by the presence of a «shelf», which indicates the twostage crystallization process. The temperature range of crystallization at slow heating (0.16 K/s) is 90 K. We analyze the peculiarities of the crystallization process of amorphous alloys under the influence of laser treatment. The high heating rates, achieved by the laser treatment of amorphous alloys, create a number of differences in the course of crystallization processes compared with crystallization during slow isothermal annealings. According to the calculations, impulse heating to temperatures below 550 K does not cause crystallization. After 551 K, there are significant changes in the crystallization kinetics. At 552 K, the crystalline phase part has reached the value of 8 %. In the interval from 552 K to 553 K, there is a sharp jump in the value of the crystal phase proportion from 8 % to 99 %, that is a complete crystallization of the amorphous alloy occurs. The calculations carried out have shown that explosive crystallization may occur during the pulsed laser annealing of binary amorphous alloys of the Fe-Zr system. The temperature at which explosive crystallization is possible due to the laser pulse was less than 60 K for the temperature of the beginning of intensive crystallization at slow heating.

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Nanocrystallization of amorphous alloys under the action of irradiation with argon ions

Tsaregradskaya,

Ovsiienko,

Kozachenko

et al. 2024

J. Phys. Stud.

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The purpose of the research is to analyze the possibility of obtaining an amorphous nanostructured state from the original amorphous state by ion irradiation. The processes of phase formation in the Fe75Mo5Si6B14 amorphous alloy under the inuence of argon ion irradiation were investigated using the methods of highly sensitive dilatometry, microhardness measurements, and electron microscopy. The surface treatment of the amorphous alloy with argon ions was carried out at a voltage on the anode of 1 kV and a current through the sample of 1 mA. The surface morphology of the amorphous alloy treated with argon ions was studied under a LensSEI scanning electron microscope. The structure of amorphous alloys is characterized by the presence of frozen-in crystallization centers.It was found that the phenomenon of nanocrystallization is not observed during exposure to ion irradiation for up to 30 minutes. This is explained by the fact that, as a result of ion irradiation, the local temperature on the surface of the sample rises and reaches such values, at which, according to the thermodynamic theory of thermal stability, the frozen centers of crystallization can dissolve in the amorphous matrix. When the ion irradiation time of the source alloy is increased to 45 minutes, a decrease in thermal stability of 25 • C and an increase in microhardness of 8.2% are observed, therefore, the alloy is strengthened. This indirectly indicates the formation of an amorphous-nanocrystalline state in the alloy. Structural changes are also conrmed by the results of studies of the amorphous alloy surface morphology by scanning electron microscopy. After irradiation, both the number of crystal nuclei and their average size increase signicantly (from 20 nm in the source alloy to 65 nm in the irradiated one). The changes in the number and size of crystal nuclei are explained by the fact that at an irradiation time of 45 minutes, the temperature in the regions of the ion tracks reaches threshold values and thermodynamic conditions are created for the growth of frozen crystallization centers.

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Controlled nanostructuring from an amorphous state in multicomponental alloys based on cobalt

Cited by 3 publications

References 0 publications

Magnetic properties and nanocrystallization behavior of Co-based amorphous alloy

Magnetic properties and nanocrystallization behavior of Co-based amorphous alloy

Initiation of the Explosive Crystallization Process in Amorphous Alloys of the Fe-Zr System by Pulse Laser Treatment

Nanocrystallization of amorphous alloys under the action of irradiation with argon ions

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