NbC precipitation in low carbon steels provides an effective way to increase the mechanical properties. However, no detailed quantitative characterisation of this precipitation is available at this date.
In this study, NbC precipitation kinetics in ferrite are investigated for two Fe-Nb-C model alloys. The volume fraction and precipitate size are followed by small-angle neutron scattering measurements. Precipitate morphology and location are determined by Transmission Electron Microscopy observations.
A specific precipitation model is developed which quantifies the role of dislocations as preferential nucleation sites and short-circuit diffusion paths.
In addition, study of precipitation kinetics in a model Fe-Cu alloy has been carried out in order to improve the understanding in the nucleation stage and in non-isothermal precipitation kinetics.