Authors: Andriy O. Koval'chuk, D.S. Gertsriken, Andriy Gusak, V.F. Mazanko

Abstract: Since 1975 a so-called anomalous mass-transfer in metals and alloys under pulse loading
is being investigated in the Institute of Metal Physics. This phenomenon remains to be a challenge
to theoreticians. Besides, one more phenomenon (observed at the same systems) was discovered –
formation of metastable alloys (solutions, and, sometimes, ordered phases), with solubility limits far
exceeding the equilibrium values and depending on the deformation rate. Since formation of nonequilibrium
phases is also typical for alloys under irradiation, it seemed natural for us to use some
of concepts and models invented in the “materials under irradiation” community. We propose 3
types of models for description of metastable solid solution formation in diffusion couple under
pulse loading: 1) flux balance for both components at the interface with account of non-equilibrium
defects generated during pulse loading; 2) “ballistic jump” concept, which had been invented by
George Martin et al. for materials under irradiation or ball-milling, combined with another Martin’s
kinetic model (1994) of diffusion; 3) modification of such a concept for the case of non-equilibrium
interstitial defects. Non-equilibrium phase diagrams obtained by all 3 models are built and
compared with experimental data which reflect a qualitative correspondence to one another.

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Authors: Ekaterina N. Kalabukhova, Dariya Savchenko, Bela Shanina, Nikolai T. Bagraev, Leonid Klyachkin, Anna Malyarenko

Abstract: Triplet center with spin state S = 1 is detected in the EPR spectrum of the self-assembled 6H SiC nanostructure obtained by non-equilibrium boron diffusion into the n-type 6H SiC epitaxial layer (EL) under conditions of the controlled injection of the silicon vacancies at the temperature of T = 900°C. From the analysis of the angular dependences of the EPR spectrum and the numerical diagonalization of the spin Hamiltonian, the value of the zero-field splitting constant D and g-factor are found to be D = 1140•10^{-4}см^{-1} and g_{par} = 1.9700, g_{per} = 1.9964. Based on the hyperfine (hf) structure of the defect originating from the hf interaction with one ^{14}N nuclei, the large value of the zero-field splitting constant D and technological conditions of the boron diffusion into the n-type 6H SiC EL, the triplet center is tentatively assigned to the defect center consisting of nitrogen atom and silicon vacancy.

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Authors: Xiang Hui Guo, Hai Yun Hu

Abstract: The non-equilibrium statistical theory was used as a theoretical approach to modeling and predicting void evolution in metal materials. Fokker-Plank equation was introduced as the kinetic equation for the void evolution, from which the probability density distribution function of voids could be obtained. From the micro-mechanism of metal's irradiation damage, void growth rate equation was obtained using spherical Weilv model and control diffusion theory, and then was simplified based on appropriate assumptions. According to the probability density distribution function of void, a series of macro-mechanical characteristics caused by void growth can be calculated, such as: the critical radius of the void nucleation, the average radius of void. Thus the correlation between the void microstructure evolution and the macroscopic properties of metals can be achieved.

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