The atomic and electronic structures of the Σ5 (210) [001] tilt grain boundary, in material with and without H impurities, were calculated by using the full-potential linearized-augmented plane-wave method. The strain field normal to the boundary plane, and the excess grain boundary volume, were calculated and were compared with the results which were obtained by using the embedded-atom method. The interlayer strain normal to the grain boundary oscillated with increasing distance from the grain boundary. The bonding charge distributions suggested that bonding in the boundary region was different to that in the bulk. Total-energy calculations showed that the H impurity preferred to occupy interstitial sites on the Ni-rich grain boundary plane. The H was found to reduce the bonding charge across the boundary plane. The grain-boundary energy and the Griffith cohesive energy for both clean and H-segregated grain boundaries were calculated and were compared with available embedded-atom model results. The H impurity was found to increase the grain-boundary energy and to reduce the Griffith cohesive energy of the boundary; thus indicating that H was a grain boundary embrittling agent.

First-Principles Studies of the Σ5 Tilt Grain Boundary in Ni3Al. Lu, G., Kioussis, N., Wu, R., Ciftan, M.: Physical Review B, 1999, 59[2], 891-8