The lattice distortion around interstitials in F.C.C. metals

The displacement field produced by the body centred interstitial and the 〈100〉 spilt interstitial in aluminium, nickel, and the noble metals is calculated using a discrete lattice model. It is assumed that the host atoms interact amongst themselves through a pairwise potential which extends out to second‐nearest neighbours and the short‐range repulsion between the interstitial and near neighbour host atoms is represented by either a Born‐Mayer or Morse potential. With the exception of aluminium the relaxation volume around the 〈100〉 spilt interstitial is similar to that around the body‐centred configuration and furthermore the differences in the results for the two potentials are quite small. For each metal the relaxation volume around an interstitial is found to be significantly larger than that previously calculated for a vacancy.