Development of the RF-MEAM Interatomic Potential for the Fe-C System to Study the Temperature-Dependent Elastic...

Area of Science:

• Materials Science
• Computational Materials Science
• Condensed Matter Physics

Background:

• Computational modeling of complex alloys like steel is hindered by the lack of accurate interatomic potentials.
• Developing versatile potentials is essential for large-scale simulations and material design.

Purpose of the Study:

• To develop a robust ReaxFF reactive force field-based modified embedded-atom method (RF-MEAM) potential for the iron-carbon (Fe-C) system.
• To accurately predict the elastic properties of Fe-C alloys at elevated temperatures.

Main Methods:

• Developed and fitted RF-MEAM potential parameters using density functional theory (DFT) data (forces, energies, stress tensors).
• Employed a two-step filtering process involving MEAMfit code and molecular dynamics (MD) simulations.
• Validated potentials by comparing calculated elastic constants and phonon spectra with DFT and experimental data.

Main Results:

• The best RF-MEAM potential accurately predicted ground-state elastic properties for B1, cementite, and orthorhombic-Fe7C3 (O-Fe7C3).
• Calculated phonon spectra for cementite and O-Fe7C3 showed good agreement with DFT results.
• Successfully predicted elevated temperature elastic properties for interstitial Fe-C alloys and O-Fe7C3, consistent with literature.

Conclusions:

• The developed RF-MEAM potential is effective for modeling elevated-temperature elastic properties of Fe-C systems.
• This potential advances the computational investigation and design of complex alloys like steel.