Numerical simulation of solidification of an iron-based binary alloy modified with nanoscale particles
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DOI: 10.1134/S0869864320030130
Numerical simulation of solidification of an iron-based binary alloy modified with nanoscale particles * V.N. Popov, A.N. Cherepanov, and V.G. Shchukin Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia E-mail: [email protected] (Received November 19, 2019; revised November 19, 2019; accepted for publication February 10, 2020) A mathematical model of solidification of an iron-based binary alloy (Fe-C) modified with nanosize highrefractory particles is proposed. The processes of alloy heterogeneous nucleation on the surface of nanosize particles and those of alloy crystallization in a cylindrical mold are described. For liquidus temperature, a linear approximation of the concentration of dissolved carbon is adopted; the law of change of this temperature obeys the non-equilibrium lever rule. The volume of the solid phase formed around a nucleus during the crystallization determines the characteristic size of the grain structure in the solidified alloy. Numerical simulation of melt solidification in a cylindrical crucible was carried out, and the kinetics of heterogeneous nucleation and growth of the solid phase was analyzed. It was found that the conditions for nucleation and crystallization differ substantially within the casting. It is shown that, as the melt undergoes cooling, volume-sequential crystallization gets established. Keywords: crystallization, binary alloy, nucleation, modification, nanosize high-refractory particles, numerical simulation.
Introduction Iron-based alloys are the main structural materials in almost all branches of modern industry. However, the problem of improving the quality and strength of the cast metal still remains a challenging one. One of the ways to solve this problem is to increase the dispersion and uniformity of the structure of the hardened alloy by adding to the melt nanosize highrefractory particles. Heterogeneous nucleation of the melt on the particles is possible depending on their size, shape, and wettability [1–4]. Specially prepared particles of SiC, TiC, and TiN can be used as the modifiers. The use of this technology allows one to increase the number of crystallization centers and, in this way, improve the dispersion and service properties of the metal. Today, many works devoted to the experimental and theoretical study of the formation of the structure of cast metals and alloys are available (see, e.g. [1, 5–9]). The technology of using nanoscale high-refractory chemical compounds in foundry is presented in [1, 10]. In [10–14], *
This work was performed as part of the Program of Fundamental Scientific Research of the State Academies of Sciences for 2013–2020 years (Project AAAA-A17-117030610136-3)
V.N. Popov, A.N. Cherepanov, and V.G. Shchukin, 2020
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V.N. Popov, A.N. Cherepanov, and V.G. Shchukin
a decrease of the mean grain size in the ingot, leading to an improvement of the strength properties of the metal, was experimentally confirmed. In [15, 16], a mathematical model of heterogene
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