Coupled experimental-computational analysis of primary static recrystallization in low carbon steel

Abstract

Primary static recrystallization is a restoration process during which the critically strong deformed microstructure is atomistically reconstructed into a polycrystal with orders of magnitude lower defect density. Advances in diffraction methods catalyzed research activities directed towards more accurate understanding of recrystallization. While these efforts rendered most mechanisms by now qualitatively well understood, many quantitative details remain still unknown. Computer simulations are a viable option to provide qualitative insights into the complex recrystallization process as they provide unlimited observability. However, simulation tools for studying recrystallization in volumes that are significantly large enough for making predictions of mean-field descriptors, such as the distribution of grain sizes or texture evolution, are typically based on continuum models. The use of such models requires to accept certain assumptions on how the collective behavior of multiple thousands of atoms can be homogenized. One aspect of special importance for continuum models is the correct prediction of the nucleation process as it influences virtually all quantitative descriptors of the recrystallized microstructure. This study presents a one-to-one comparison of simulation results to quasi in situ scanning electron microcopy/electron backscatter diffraction results revealing how two different assumptions for the crystallographic orientation of the nuclei perform in reproducing the experimentally observed recrystallization microstructure. Moreover, by comparing the recrystallized microstructure at the surface and in the interior of the three-dimensional model, it is shown how quasi in situ experiments systematically underestimate the recrystallization rate and predict a distorted grain size distribution.