Electronic Effects of Sulfur in Nickel: A Model for Grain Boundary Embrittlement

摘要

This paper reports the first study employing detailed electronic structure calculations to investigate a model of grain boundary embrittlement. The results show that adding sulfur to a cluster of nickel atoms causes strong bonds to be formed between the sulfur atom and the nickel atoms nearest to it, while simultaneously weakening bonds between these nickel atoms and their neighboring nickel atoms in the cluster. As a consequence one can suggest that sulfur forms very strong bonds within the plane of the boundary but weakens metal-metal bonds perpendicular to this plane. Although, for the present, the results can be considered only as suggesting one possible embrittlement mechanism, they do demonstrate the insight which such calculations can provide into this very central question of grain boundary embrittlement. (Author)