Publications (4)1.03 Total impact
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Article: Experimental and theoretical study of processes of formation and growth of pearlite colonies in eutectoid steels
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ABSTRACT: We describe our optical and electron-microscopy observations of pearlite structures in eutectoid steels which seem to imply that the mechanisms of formation of pearlite colonies in these steels differ from those observed earlier for non-eutectoid steels. A simple theoretical model to study kinetics of pearlite transformations is suggested. Simulations of growth of pearlite colonies based on this model reveal that for the volume carbon diffusion mechanism usually-supposed such growth is always unstable, and the steady-state growth can be realized only via the interfacial carbon diffusion mechanism. A model of formation of pearlite colonies based on the assumption of a strong enhancement of carbon diffusion near grain boundaries is also suggested. The model can be applicable to the plastically deformed steels, and the results of simulations based on this model qualitatively agree with some microstructural features of formation of pearlite colonies observed in such steels. Comment: 12 pages, 23 figures11/2010; -
Article: Stochastic statistical theory of nucleation and evolution of nano-sized precipitates in alloys with application to precipitation of copper in iron
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ABSTRACT: The consistent and computationally efficient stochastic statistical approach (SSA) is suggested to study kinetics of nucleation and evolution of nano-sized precipitates in alloys. An important parameter of the theory is the size of locally equilibrated regions at the nucleation stage which is estimated using the "maximum thermodynamic gain" principle suggested. For several realistic models of iron-copper alloys studied, the results of the SSA-based simulations of precipitation kinetics agree well with the kinetic Monte Carlo simulation results for all main characteristics of microstructure. The approach developed is also used to study kinetics of nucleation and changes in microstructural evolution under variations of temperature or concentration. Comment: 19 pages, RevTeX, 15 postscript figures, 8 jpeg figures, fig. 14 corrected11/2009; -
Article: Kinetics of the eutectoid colony growth in a solid solution for simple alloy models
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ABSTRACT: A simple model, which reflects the main features of the phase equilibria between austenite, ferrite, and cementite, is proposed to study the growth kinetics of pearlite-type eutectoid colonies. The previously developed microscopic theory of diffusional phase transformations in alloys developed earlier is used to simulate steady-state colony growth for several versions of this model. The existing phenomenological approaches are found to describe the main features of the colony growth kinetics qualitatively correctly; however, these approaches are insufficient to draw quantitative conclusions. The changes in the colony front shape as temperature T approaches eutectic point T e and the structure of the interphase boundaries at various T are studied. At T near T e , the initial phase (austenite) is found to wet the boundaries between the forming phases (ferrite, cementite), which results in a sharp increase in the interphase boundary thickness and a decrease in the junction angle between the phases at the colony front. The differences in the diffusion mobilities of interstitial (carbon) atoms in different phases are shown to be important to adequately describe the colony growth kinetics.Journal of Experimental and Theoretical Physics 01/2008; 107(1):90-101. · 1.03 Impact Factor -
Article: Stochastic statistical approach to the kinetics of the first stages of phase separation in alloys
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ABSTRACT: The earlier-developed statistical methods for nonequilibrium alloys are generalized to stochastically describe the evolution of microstructure at the first stages of phase separation in alloys. An important parameter of the theory is the size of locally equilibrated regions, which is estimated by using simulations at different values of this parameter. The approach is used to study the microstructural features of both the nucleation and growth (NG) and the spinodal decomposition (SD) types of evolution, as well as the morphological transition NG-SD under variations of c and T across the spinodal curve. We also investigate morphology of precipitates and kinetic features of precipitation at low temperatures. The results obtained agree well with the available experimental observations and Monte Carlo simulations.Phys. Rev. B. 77(13).
