Molecular Dynamics Investigation of TiN Precipitation in Ti-Bearing Microalloyed Steel During Solidification

LG Zhu and XD Liang and W Chen and FJ Sun and Y Li and GY Yang, METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE, 56, 2949-2961 (2025).

DOI: 10.1007/s11663-025-03528-5

The integration of titanium (Ti) into steel via microalloying markedly enhances the material's strength and overall quality. The precipitation of TiN 'beneficial' inclusions has attracted significant interest in scholarly studies both nationally and globally. This study employs the embedded-atom interaction potential (MEAM) within molecular dynamics theory to examine the precipitation behavior of TiN during the solidification of Ti-bearing microalloyed steels, as well as to elucidate the formation mechanism of TiN cluster molecules in steel and their impact on crystal transformation. The results demonstrate that Ti and N atoms in Ti-bearing microalloyed steel display reciprocal attraction, promoting the formation of Ti-N clusters. These clusters undergo incessant movement and collision propelled by potential energy, facilitating their growth and development. As a result, stable TiN inclusions with diameters greater than 33 atoms are generated. These inclusions exhibit considerable mobility and a diffuse dispersion along grain boundaries during solidification, hence refining the austenitic grains. The uniformly distributed TiN at grain boundaries is essential for facilitating austenite grain refining during solidification. This paper clarifies the principal experimental phenomena observed during the solidification process concerning the formation of nano-beneficial inclusions in molecular dynamics simulation and analysis, as well as an analysis of the solidification process in steel containing TiN beneficial inclusions, focusing on grain refinement to improve the material's strength and toughness.

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