Crystal plasticity finite element simulation of lattice rotation and x-ray diffraction during laser shock-compression of Tantalum

• Published in: arXiv.org 2021-08
• Main Authors: Avraam, P, McGonegle, D, Heighway, P G, Wehrenberg, C E, Floyd, E, Comley, A, Foster, J M, Turner, J, Case, S, Wark, J S
• Format: Article
• Language: English
• Subjects: Crystal lattices; Deformation; Finite element method; Free electron lasers; Kinetics; Lasers; Nucleation; Plastic properties; Polycrystals; Rotation; Slip; Tantalum; Twinning; X-ray diffraction
• ISSN: 2331-8422

Wehrenberg et. al. [Nature 550 496 (2017)] used ultrafast in situ x-ray diffraction at the LCLS x-ray free-electron laser facility to measure large lattice rotations resulting from slip and deformation twinning in shock-compressed laser-driven [110] fibre textured tantalum polycrystal. We employ a crystal plasticity finite element method model, with slip kinetics based closely on the isotropic dislocation-based Livermore Multiscale Model [Barton et. al., J. Appl. Phys. 109 (2011)], to analyse this experiment. We elucidate the link between the degree of lattice rotation and the kinetics of plasticity, demonstrating that a transition occurs at shock pressures of \(\sim\)27 GPa, between a regime of relatively slow kinetics, resulting in a balanced pattern of slip system activation and therefore relatively small net lattice rotation, and a regime of fast kinetics, due to the onset of nucleation, resulting in a lop-sided pattern of deformation-system activation and therefore large net lattice rotations. We demonstrate a good fit between this model and experimental x-ray diffraction data of lattice rotation, and show that this data is constraining of deformation kinetics.