Article
Surface Crystallization and Magnetization-Reversal Processes in Amorphous Microwires
Amorphous microwires of Fe73.8Si13B9.1Cu1Nb3.1 and Fe77.5Si13.5B9 composition fabricated by the Ulitovsky– Taylor method were studied. The samples with the glass shell removed were heated at temperatures of 753 K and 703 K for 20 min, afterwards, their structure was examined using X-ray diffraction. Subsequently, the thermally treated samples were chemically etched and X-ray diffraction study of the structure was again carried out. Experimental results on the predominant crystallization of near-surface regions were discussed assuming that mechanical stresses affect the nucleation and growth of nanocrystals.
The influence of heat treatment and deformation on structural changes of Al-based amorphous alloys in the amorphous state and at early stages of crystallization has been studied using the methods of X-ray diffraction, differential scanning calorimetry and transmission electron microscopy. It is shown that isothermal annealing and multiple cold rolling bring about formation of an inhomogeneous amorphous phase with the areas of different chemical composition. The formation of an inhomogeneous amorphous phase accelerates the process of nanocrystallization of Al-based alloys. The conditions of treatment of the amorphous alloy in the amorphous state affect the size and fraction of nanocrystals forming in the amorphous phase upon subsequent heating. The size of nanocrystals in the case of preliminary deformation is smaller than that upon preliminary isothermal annealing. We discuss the reasons for the formation of nanostructures containing smaller nanocrystals in the case of thermal and deformation treatments before the onset of crystallization.
The structure of silicon crystals implanted with protons was studied by methods of high-resolution X-ray diffraction . The distribution of strain in the disturbed layers was analyzed.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.