Modelling thermodynamics of nanocrystalline binary interstitial alloys

Grain boundary (GB) segregation in nanocrystalline alloys can cause reduction of GB energy, which leads to thermodynamic stabilization of nanostructures. This effect has been modelled intensively. However, the previous modelling works were limited to substitutional alloy systems. In this work, thermodynamics of nanocrystalline binary interstitial alloy systems was modelled based on a two-sublattice model proposed by Hillert [M. Hillert, et al. Acta Chem. Scand., 24 (1970) 3618] and an atomic configuration for nanocrystalline systems proposed by Trelewicz and Schuh [J.R. Trelewicz, et al. Physical Review B, 79 (2009) 094112]. The modelling calculations agree with the reported experimental data, indicating that the current thermodynamic model is capable of accounting for the alloying effect in the nanocrystalline binary interstitial alloys.