Modelling of carbo-nitride nucleation in 10% Cr steel

The present work is a part of a project, where the aim is to predict the behaviour of high-temperature steels during heat treatment and operation at high temperatures in steam turbines. An attempt to model nucleation of M(C, N) particles is presented. M stands for one or several carbide or nitride stabilising alloy elements. The classical nucleation theory was developed for pure substances and for binary solutions. However, real steels are multicomponent in nature, and thus the situation becomes more complex and the classical theory is now extended to include such cases. The model rakes fully into account the thermodynamic properties of the multicomponent alloys and the effect of transformation stresses as well as nucleation on dislocations is accounted for in a simplified manner. The new model is applied to so-called 10% Cr steels.