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9LM-P-5
LASER-MATTER INTERACTION
Atomistic modeling of mobility of solid/liquid interfaces of melting/ crystallization of metals Al, Cu, Fe under deep overheating/undercooling
conditions
A.V. Mazhukin, A.V. Shapranov, O.N. Koroleva, V.I. Mazhukin
ALT'22
Keldysh Institute of Applied Mathematics of RAS, Moscow, Russia
vim@modhef.ru
Ultrashort pulsed fs-ps-laser action on various materials leads to consideration of a number of important fundamental problems, which at high heating rates include the features of heterogeneous melting/solidification mechanisms and the associated ultimate overheating and undercooling of matter. The speed of movement of the solid/liquid interface (SLI) usl plays an important role in crystallization/melting processes, and is one of the fundamental concepts of materials science. Based on the analysis of kinetic models of melting/crystallization with diffusion and collisional-thermal confinement, a modification of the transition state theory is performed, which forms the basis of the Wilson - Frenkel kinetic model developed at the beginning of the 20th century. The modification consists in replacing constant coefficients in the forward and reverse transition rates with a functional temperature dependence of the solid/liquid interface Tsl [1]. Using 3 EAM interaction potentials for Al, Cu, Fe and the molecular dynamics method, atomistic modeling of melting/ crystallization of metals (Al, Cu, Fe) under conditions of deep overheating/overcooling has been performed.
By comparing the results of atomistic modeling with the data of the modified kinetic model for three metals, the temperature dependences of the response function usl were plotted in the range of maximum allowable overheating/ overcooling values. The modification of the Wilson - Frenkel model is essentially a new kinetic model [2] and allows one to obtain for metals the temperature diffusion-limited dependences of the velocity of the interface usl, described by the same equation in the entire temperature range.
The temperature dependences of the solid/liquid interface velocity, determined from the results of modeling using both interaction potentials, demonstrate a clear asymmetry with respect to the melting point Tm, which is explained by the strong difference between the solidification kinetics in a strongly undercooled state and the kinetics of melting in a highly superheated state.
This work was supported by Russian Science Foundation (project No. 18-11-00318).
[1] Mazhukin, V.I., Shapranov, A.V., Perezhigin, V.E. et al. Kinetic melting and crystallization stages of strongly superheated and supercooled metals. Math Models Comput Simul. 9, 448-456 (2017). https://doi.org/10.1134/S2070048217040081
[2] Mazhukin, V.I., Shapranov, A.V., Mazhukin, A.V. Atomistic modeling of the dynamics of the solid/liquid interface of Si melting and crystallization taking into account deeply superheated/ supercooled states. Math. Montis, 47, 87-99 (2020). DOI: 10.20948/ mathmontis-2020-47-8.
