Anisotropy of grain boundary segregation in Σ = 5 bicrystals of α-iron

Abstract Based on AES measurements of temperature dependencies of P, Si and C segregation at the Σ = 5, 36.9° [100] tilt grain boundaries of well-defined bicrystals of an Fe-3.5at%Si alloy, the anisotropy of grain boundary segregation was determined. It was found that not only the two {013} and {012} symmetrical grain boundaries exhibit special behavior but also the (001)/(03 4 ) and (0 1 7)/(01 1 ) asymmetrical grain boundaries. All these boundaries are characterized by high values of the effective interplanar spacing. The measured data allow the construction of the first experimental grain boundary segregation diagram in terms of segregation enthalpy, solid solubility and boundary orientation.