Pressure-induced phase transformations in Fe-C: Molecular dynamics approach

Molecular dynamics simulations provide a large body of literature on pressure-induced phase transformations in iron. However, the role of interstitial carbon on phase transformations in iron under high pressure is still an open topic. We investigate the mechanical response of Fe-C single crystals and polycrystals using hydrostatic and uniaxial compression. We couple a recently developed Fe interatomic EAM potential, which faithfully describes the alpha -> epsilon transformation in iron, with several well-known Fe-C potentials. Our results show a three-wave profile demonstrating that the phase transformation is preceded by plasticity. Carbon strongly increases the transformation pressure but decreases the Hugoniot elastic limit in agreement with experimental results.