Results of measurements of positron lifetimes and X-ray diffraction in the annealed metallic glasses Fe_{78-x}Co_{x}Si_{9}B_{13} (x = 0, 20, 40, 60, 78) before and after the process of crystallization are presented. From the results it follows that the annealing process below the crystallization temperature causes changes in concentrations of positron-trapping areas and can be consistently described as the result of two contributions: topological and chemical short range ordering. The process of crystallization causes precipitation of α-Fe and β-Co crystalline phases and also formation of microvoids in the investigated samples.
An approach to structural characterization of chalcogenide glasses based on the study of void distribution is discussed. The results of positron annihilation lifetime spectra measurements for glassy-like g-As_2Se_3 are compared with nano-void distribution data obtained from Monte Carlo simulation. In this consideration perspectives to involve the parameters of nano-voids calculated from the first sharp diffraction peak in the framework of known Elliott's model are analyzed.
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Structural changes accompanying the isothermal annealing of the metallic glass Fe_{18}_{C}o_{60}Si_{9}B_{13} were investigated by X-ray diffraction, positron annihilation as well as by electrical resistivity and the Hall resistivity measurements. It has been found out that at the temperature of 673 K the complete crystallization did not occur, but only a few nuclei of the α-Fe phase, which did not grow, were formed.
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In the present work, the influence of annealing conditions on magnetic properties and phase constitution of the rapidly solidified Fe₆₅Pr₉B₁₈W₈ alloy ribbons, were investigate. Samples were prepared by arc-melting of high purity constituent elements under the Ar atmosphere. Ribbons were obtained by melt-spinning technique under low pressure of Ar. The ribbons in as-cast state had amorphous structure and soft magnetic properties. Heat treatment, carried out at various temperatures (from 923 K to 1023 K) for 5 min, resulted in an evolution of the phase constitution that caused changes in magnetic properties of the alloy. The crystallization behavior was studied using differential scanning calorimetry and X-ray diffractometry. The room temperature magnetic properties were determined from hysteresis loops measured by VSM magnetometer in the external magnetic field up to 2 T.
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The aim of the present work was to investigate the phase constitution and magnetic properties of the rapidly solidified Fe₆₅Pr₉B₁₈W₈ alloy ribbons in the as-cast state and subjected to annealing. The base alloy was prepared by arc-melting of the high purity elements under the Ar atmosphere. The ribbon samples were obtained by the melt-spinning technique under a low pressure of Ar. The studies have shown an amorphous structure of the ribbon in the as-cast state and its soft magnetic properties. Annealing at various temperatures for 5 min resulted in an evolution of the phase constitution that caused changes in magnetic properties of the alloy. The crystallization behavior was studied using differential scanning calorimetry. In order to determine the phase composition of annealed ribbons, X-ray diffractometry was used. The evolution of microstructure and phase constitution was verified by the Mössbauer spectroscopy. The magnetic properties were determined from hysteresis loops measured by a vibrating sample magnetometer in the external magnetic field up to 2 T at room temperature.
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