In situ transmission electron microscopy investigations of the kinetics of α″-Fe16N2 precipitation during the ageing of nitrogen–ferrite

In situ transmission electron microscopy investigations were carried out on a supersaturated nitrogen–ferrite to characterise the precipitation kinetics of α″-Fe16N2 nitrides at 85 °C. The coarsening behaviour consists of two stages. The first stage obeys the LSW theory and the coarsening rate was determined as 11.2 nm3 s−1. The second stage corresponds to the stabilization of coarsening, and was assumed to be related to the coherency loss between the precipitates and the matrix.