Examination of the particle-affected deformation zone in polycrystalline materials

The determination of strain distribution in polycrystalline materials plays an important role in the description of the nucleation phenomenon during recrystallisation. The strain is highly inhomogeneous in the vicinity of the rigid second-phase particles, promoting highly localized Particle-Stimulated Nucleation (PSN).

An efficient approach to describing the local effect in the Particle-Affected Deformation Zone (PADZ) is applying mechanically based simulation to the known macroscopic deformation mode. In this research, a kinematically admissible velocity field is defined for the widely assumed plane-strain compression, tensile load. The model is generalized for complex loads containing various normal and shear components.

The results are validated against nanohardness measurements performed on cold-rolled metallic specimens from alloyed aluminum material containing rigid secondary-phase particles. The local results are compared not only to locally measured values, but to simulated results from finite element analysis of elasto-plastic deformable materials.

Comparison of the modelled and measured values shows that the newly developed model is able to describe the local, microscopic deformation process by knowing the macroscopic deformation mode. The computationally efficient model gives a good understanding of the Particle-Affected Deformation Zone’s (PADZ) evolution with the increasing macroscopic strain. The model and the measurements connect the processes on macroscopic and microscopic levels in a computationally efficient way, making the recrystallisation a multiscale problem.