The influence of lead on mechanical properties of BCC and FCC iron from a constructed bond-order potential

DK Peng and JL Hu and YC Jiang and L Sun and HR Gong and LY Yang and CP Liang, EUROPEAN PHYSICAL JOURNAL PLUS, 138, 1082 (2023).

DOI: 10.1140/epjp/s13360-023-04668-w

To design and apply liquid Pb as coolant in nuclear reactors, it is important to understand its atomic behaviors with the steel container through molecular dynamics (MD) simulations. A reliable and capable Fe- Pb potential is the key to the MD simulations. In this work, an analytical bond-order potential (BOP) of Fe-Pb has been constructed through the data-fitting of various phases from experiments and first- principles calculations. The newly constructed potential has a better performance in predicting different Fe-Pb phases than the Fe-Pb potentials already published in the literature. Molecular dynamics simulations based on this BOP have been conducted to study the effect of Pb on bulk and grain boundary of BCC and FCC iron. For bulk iron, it is found that of the addition of Pb decreases the elastic constants, elastic moduli, and ductility of BCC Fe more significant than that of FCC Fe. The calculations of two typical tilt symmetrical grain boundaries of Fe and Fe96Pb4 indicate that the appearance of Pb would cause a more considerable brittleness for BCC Fe than that for FCC Fe. The obtained results are in good agreement with similar experimental observations in the literature, which not only provides a strong support to the reliability of newly constructed Fe-Pb potential, but sheds lights on the understanding of mechanical properties of Fe-Pb system.

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