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 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. This study presents a one-to-one comparison of simulation results to quasi in situ Scanning Electron Microcopy/Electron Backscatter Diffraction (SEM/EBSD) 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.
Bio
Martin Diehl is currently a project group leader for Integrated Computational Materials Engineering (ICME) in the department for Microstructure Physics and Alloy Design headed by Dierk Raabe at the Max-Planck-Institut für Eisenforschung in Düsseldorf, Germany. He obtained his diploma degree (master equivalent) in 2010 from TU München in mechanical engineering and his PhD from RWTH Aachen University in 2016 in materials science and engineering. After that he worked as a post doctoral researcher in the Theory and Simulation group under the supervision of Franz Roters in the Max-Planck-Institut für Eisenforschung. Martins scientific interests lay in the continuum modeling of structural materials at engineering time and length scales. To this ends, he is the main developer of the Düsseldorf Advanced Materials Simulation Kit (DAMASK). DAMASK contains a variety of crystal plasticity models together with modules for the description of damage and temperature. A special focus of Martin’s work is joint computational–experimental work. This includes for example the use of experimentally characterized microstructures as input for simulations.
Host: Professor Nikhil Admal
