The kinetics of martensitic nucleation in iron based alloys

On the basis of the classical martensitic nucleation theory, the activation energy of homogeneous nucleation in iron based alloys were reconsidered. A extensive study was made to determine the dependence of activation energy on the interfacial energy and the driving force of martensitic transformation. It is indicated that thermal activated nucleation possesses very small activation energy, which is compatible with relevant experimental investigations. On this context, a nucleation mechanism was developed, attempting to explain the origin of martensitic nucleation in iron based alloys. In this mechanism, in addition to thermal activation, the contribution of mechanical driving force to the nucleation was taken into account, particular in the case of martensitic transformation at low temperature.