Solute segregation to ferrite grain boundaries in nodular cast iron: experiment and prediction

Grain boundary segregation belongs to the phenomena affecting predominantly mechanical properties of polycrystalline materials. Although extended studies of interfacial phosphorus segregation have been done in low-alloy steels, no information is available on segregation of this impurity to ferrite grain boundaries in cast irons. In this contribution we describe chemical composition of grain boundaries of the ferrite phase in nodular cast iron. Auger electron spectroscopy (AES) measurements are compared with the prediction of chemical composition based on the recently proposed thermodynamic models (the relationship between the enthalpy of solute segregation and the solid solubility, and the compensation effect). Both these general relationships are applied to predict the segregation of any solute at any grain boundary: this prediction offers a substantial extension of the database on grain boundary segregation. Copyright (c) 2008 John Wiley & Sons, Ltd.