The role of plastic heterogeneity for texture formation during recrystallization of iron alloys

When metals are deformed they obtain a crystallographic texture that is typical of the crystal structure and the applied strain field. During annealing of a plastically deformed metal recrystallization may occur, which produces a recrystallization texture. Even though progress has been obtained in the past decades, the precise details of the change of a deformation to a recrystallization texture are still poorly understood. It is the aim of the present project to obtain a more accurate understanding of the local orientation changes during plastic deformation of iron alloys with BCC crystal structure, as it is commonly accepted that local orientation gradients appearing in the vicinity of grain boundaries or as a result of plastic instabilities, such as shear--‐bands, play a crucial role in the formation of the recrystallization texture. In continuum mechanics, texture changes during plastic deformation can be modelled with reasonable accuracy by crystal plasticity models. Such models, however, are only accurate in a statistical manner, i.e. given the initial texture of the material they allow simulating the average change of crystal rotation, but they do not take into account local topology of the microstructure and hence these models are not suitable for predicting the orientation change at the local scale. Each individual grain of the polycrystalline aggregate might substantially deviate from the nominal average behaviour prescribed by crystal plasticity theory, as an individual grain is constraint by the local boundary conditions imposed by the local topology of the microstructure. Such local deviations may average out in a mean--‐field approach, which explains the overall success of the continuum mechanics crystal plasticity models, but will be of crucial importance for the nucleation behaviour during recrystallization.