A method for evaluating the Griffith work of interfacial separation was proposed which was based upon first principles. It was used to investigate segregation effects at a Σ = 11 [1¯10]/(11¯3) grain boundary in the γ-phase. The chemical interaction of segregated substitutional Cr and Mn could enhance the cohesion of the grain boundary via anisotropic bonding. This weakened the bonds in the grain-boundary plane, and strengthened those in the vertical plane. However, the associated structural relaxation contributions were detrimental to the cohesion of the grain boundary. Upon combining these 2 contributions, Cr was found to act as a cohesion-enhancer while Mn acted as an embrittler. Interstitial segregants (C, N) could increase the cohesion of the grain boundary by forming strong bonds with their neighboring Fe atoms and by restraining relaxation of the surrounding Fe atoms. The ability of C and N to improve the properties of the grain boundary depended upon the environment of the segregation site.

First-Principles Study of Segregation Effects on the Cohesion of a FCC Grain Boundary. R.Yang, Y.M.Wang, H.Q.Ye, C.Y.Wang: Journal of Physics - Condensed Matter, 2001, 13[20], 4485-93