Regensburg 2019 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 29: Microstructure and Phase Transformations

MM 29.2: Talk

Wednesday, April 3, 2019, 15:15–15:30, H46

Reverse engineering the kinetics of grain growth from time-resolved 3DXRD measurements — •Mingyan Wang¹, Jules M. Dake¹, Søren Schmidt², and Carl E. Krill III¹ — ¹Ulm University, Germany — ²Technical University of Denmark, Denmark

Though grain growth has been studied in polycrystalline materials for many years, our understanding of the underlying mechanisms remains incomplete. Even in the case of normal grain growth, computer simulations differ significantly from experimental findings. Instead of modeling this phenomenon using boundary parameters derived from physical principles, we decided to try out the opposite approach: that is, to work backwards from experimental measurements to the kinetics of boundary migration. Employing 3D x-ray diffraction (3DXRD) microscopy, we investigated grain growth in two different Al alloys. In a series of microstructural snapshots taken between isothermal annealing steps, we followed the morphology, misorientation and migration of thousands of grain boundaries (GBs) in a single sample. The results enable us to extract the dependency of reduced mobility (the product of GB mobility and energy) on GB misorientation. In one particular specimen, this dependency is consistent with expectations for normal grain growth, but, in the other case, we find evidence for abnormal kinetics that do not fit standard models.