Data for Modelling defects in Ni-Al with EAM and DFT calculations

We find that the EAM interatomic potentials reproduce low-temperature structural properties in both the γ and ${{\gamma}^{\prime}}$ phases, and yield accurate atomic forces in bulk-like configurations even at temperatures as high as ~1200 K. However, they fail to describe more complex chemical bonding, in configurations including defects such as vacancies or dislocations, for which we observe significant deviations between the EAM and DFT forces, suggesting that derived properties such as (free) energy barriers to vacancy migration and dislocation glide may also be inaccurate.

Testing against full DFT calculations further reveals that these deviations have a local character, and are typically severe only up to the first or second neighbours of the defect. This suggests that a QM/MM approach can be used to accurately reproduce QM observables, fully exploiting the EAM potential efficiency in the MM zone. This approach could be easily extended to ternary systems for which developing a reliable and fully transferable EAM parameterisation would be extremely challenging e.g. Ni alloy model systems with a W or Re-containing QM zone.<br><br>Data for 'Modelling defects in Ni-Al with EAM and DFT calculations', F. Bianchini J.R. Kermode and A. De Vita, MSMSE (2016) DFT theory data genereated using vasp.5.3.3 standard input and output files provided the EAM potential can be downloaded from ctcms.nist.gov/potentials/Ni.html directory are labelled using the number of the related figure in the paper fig1/bulk_shifts DFT data for (a) fig1/CHGCAR charge density for (b) fig2/gamma data for simulations at different temperature (300 K,600 K,900 K,1200 K) fig2/gamma_prime data for simulations at different temperature (300 K,600 K,900 K,1200 K) fig3/gamma data for periodic systems (1200 K) and for clusters carved from them for bulk gamma fig3/vacancy data for periodic systems (1200 K) and for clusters carved from them for a gamma-vacancy fig4/dislocation data for cluster carved around a dislocation core in gamma (1200 K) fig5_6/rhenium/periodic Rhenium impurity in gamma in a periocic cell (1200 K).