Viscosity and structure correlation mechanism of Fe-Cr-C melt based on MD simulation

YJ Zhang and KX Jiao and JL Zhang and XY Fan and SC Gao, JOURNAL OF MOLECULAR LIQUIDS, 413, 125903 (2024).

DOI: 10.1016/j.molliq.2024.125903

The viscosity of Fe-C-Cr melt affects the mass transfer behavior during steelmaking processes. Reasonable regulation of viscosity can improve production efficiency. There is a close relationship between melt viscosity and structure. Therefore, it is of great theoretical significance to analyze the correlation between viscosity and structure of chromium-containing iron melt for the optimization of the whole metallurgical process. This study experimentally investigated the viscosity of Fe-C-Cr melt and utilized molecular dynamics simulation to analyze the formation and growth behavior of atomic clusters, revealing the correlation mechanism between structure and viscosity. As the Cr content increased from 11 % to 13 %, the melt viscosity increased by 10.05 %. At a temperature range from 1773 K to 1473 K, the viscosity reached a maximum of 15.5 mPas, representing a 40.9 % increase. Simulation results indicated that Cr-C clusters within the melt act as intermediaries, connecting with Cr-Fe and Fe-C clusters to form Fe-Cr-C clusters. The key influence of increased Cr content on viscosity lies in promoting the generation of Fe-Cr-C multicomponent clusters, while the key influence of temperature reduction lies in promoting cluster growth. With the increase in Cr content, the number of clusters at 1773 K increased from 154 to 175, and the average volume of clusters increased from 212 & Aring;(3) to 224 & Aring;(3). When the temperature decreased from 1773 K to 1473 K, the number of clusters increased by 51.2 %, and the average volume of clusters increased by 18.75 %. In comparison, the thermal state change had a greater impact on clusters, where temperature reduction led to rapid cluster growth, reduction of free volume within the melt, and ultimately resulted in increased viscosity due to the combined effects.

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