Influence of C concentration on elastic moduli of α′-Fe_1-xC_x alloys

Abstract

The elastic constants of tetragonally distorted ${\mathit{\alpha }}^{\prime }$-${\text{Fe}}_{1-x}{\text{C}}_x$ crystallites are calculated for several available interatomic interaction potentials. Besides embedded-atom-method-type potentials also a simple pair potential, modified embedded-atom-method and bond-order potentials are investigated. Care is taken to minimise the crystal structure properly in the presence of the C interstitials; we verify that the influence of statistics, i.e. the randomness of the C positions in the lattice, affects the elastic properties only little, as long as C is not allowed to cluster. We find that both sign and order of magnitude of the tetragonal elastic constants vary strongly between the predictions of the available potentials. Recent experimental data are available for the orientation-averaged elastic moduli; in contrast to the tetragonal constants, they feature only a mild dependence on C content. The experimental data are well reproduced by several of the potentials studied here. Existing deviations between experiment and predictions are discussed.

Keywords:

• Iron alloys
• martensitic steels
• elastic behaviour
• molecular dynamics

Notes

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Deutsche Forschungsgemeinschaft via the Sonderforschungsbereich 926. Simulations were performed at the High Performance Cluster Elwetritsch (RHRK, TU Kaiserslautern, Germany).