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 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 methodsComment: V. Dubinko, R. Shapovalov, Theory of a quodon gas. With application to precipitation kinetics in solids under irradiation. (Springer International Publishing, Switzerland, 2014

Experimental evidence of two-band behavior of MgB2

The break-junction tunneling has been systematically investigated in MgB2. Two types of the break-junction contacts have been exploited on the same samples, which demonstrated tunnel contact like (SIS) and point contact like (SnS) behavior. Both of them have shown the existence of the two distinct energy gaps. We have observed also the peculiarities on the I(V)- characteristics related to Leggett's collective mode assisted tunneling. --> Corresponding author address: [email protected]: 14 pages, 6 figures, 1 table; corrected typos and fig

Progress in modelling the microstructural evolution in metals under cascade damage conditions

In recent years, it has been shown that intra-cascade clustering of vacancies and self-interstitial atoms (STAs), differences in the thermal stability and mobility of the resulting clusters and one-dimensional (1-D) diffusional glide of SIA clusters play a key role in damage accumulation in metals under cascade damage conditions. The model taking these aspects into account (production bias model, PBM) succeeded in rationalising striking features in the microstructural evolution in pure metals, where the conventional rate theory model failed: the high overall swelling even at low dislocation densities, the enhanced swelling near grain boundaries, the decoration of dislocations with SIA loops, saturation of void growth and Void lattice formation. In the present paper, the main ideas and results of these considerations are reviewed. We discuss recent work on possible effects of deviations of SIA cluster diffusion from strictly 1-D by direction changes and/or self-climb and formulate a general reaction kinetics including 1-D and 3-D cluster diffusion. Such reaction kinetics may be considered to form the basis for a general description of cascade damage accumulation in metals and complex technical alloys. (C) 2000 Elsevier Science B.V. All rights reserved