Deformation-induced non-equilibrium grain boundary segregation in dilute alloys

On the basis of the vacancy-solute complex mechanism, a model describing deformation-induced non-equilibrium grain boundary segregation of solute is established for dilute alloys, which includes the quasi-thermodynamics and kinetics. The model is applied to the evaluation of non-equilibrium grain boundary segregation of boron during high temperature plastic deformation in an austenitic steel microstructure. The deformation-induced non-equilibrium segregation increases with decreasing temperature and is considerably larger than the thermal equilibrium one, especially in the temperature range below similar to 750 degrees C. In addition, at a given temperature the non-equilibrium segregation augments with rising strain rate as the deformation-created supersaturated vacancy concentration increases. The predictions are generally consistent with some experimental observations. (C) 2007 Elsevier B.V. All rights reserved.