Theory of a Quodon Gas with Application to Precipitation Kinetics in Solids Under Irradiation
Rate theory of the radiation-induced precipitation in solids is modified with account of non-equilibrium fluctuations driven by the “gas” of lattice solitons (a.k.a. “quodons”) produced by irradiation. According to quantitative estimations, a steady-state
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Abstract Rate theory of the radiation-induced precipitation in solids is modified with account of non-equilibrium fluctuations driven by the “gas” of lattice solitons (a.k.a. “quodons”) produced by irradiation. According to quantitative estimations, a steady-state density of the quodon gas under sufficiently intense irradiation can be as high as the density of phonon gas. The quodon gas may be a powerful driver of the chemical reaction rates under irradiation, the strength of which exponentially increases with irradiation flux and may be comparable with strength of the phonon gas that exponentially increases with temperature. The modified rate theory is applied to modelling of copper precipitation in FeCu binary alloys under electron irradiation. In contrast to the classical rate theory, which disagrees strongly with experimental data on all precipitation parameters, the modified rate theory describes quite well both the evolution of precipitates and the matrix concentration of copper measured by different methods.
1 Introduction Radiation damage in crystals caused by energetic particles (gamma, electrons, neutrons, light and heavy ions, etc.) is traditionally characterized by the numbers of point defects, i.e. vacancies and self-interstitial atoms (a.k.a. Frenkel pairs) and their clusters produced in displacement events. Their subsequent evolution is governed by diffusion, which leads to segregation of point defects into vacancy and interstitial clusters, dislocation loops and voids, a.k.a. extended defects. The difference in the ability to absorb point defects by extended defects is one the main driving force of microstructural evolution under irradiation. A recovery from
V. Dubinko () R. Shapovalov NSC Kharkov Institute of Physics and Technology, Kharkov 61108, Ukraine e-mail: [email protected] R. Carretero-González et al. (eds.), Localized Excitations in Nonlinear Complex Systems, Nonlinear Systems and Complexity 7, DOI 10.1007/978-3-319-02057-0__14, © Springer International Publishing Switzerland 2014
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V. Dubinko and R. Shapovalov
radiation damage is traditionally thought to be driven by thermal fluctuations resulting in the evaporation of single vacancies or atoms from extended defects. These are examples of Schottky defects, defined as point defects ejected from an extended defect [1]. Another driver for radiation-induced microstructural evolution is based the forced atomic relocations resulting from nuclear collisions, a.k.a. ballistic effects [2] that have been taken into account for the explanation of the dissolution of precipitates under cascade damage. Later on it was recognized that the so-called “thermally activated” reactions may be strongly modified by irradiation resulting in the radiation-induced production of Schottky defects [1,3–6], which has essentially the same physical nature as the ballistic effects [12], but, in contrast to the latter, it operates under both cascade and non-cascade damage conditions, including sub-threshold electron irradiation that does not produce stable
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