Dynamic crystal plasticity modeling of single crystal tantalum and validation using Taylor cylinder impact tests

• Published in: International journal of plasticity Vol. 139; no. C; p. 102940
• Main Authors: Nguyen, Thao, Fensin, Saryu J., Luscher, Darby J.
• Format: Journal Article
• Language: English
• Published: New York Elsevier Ltd 01.04.2021; Elsevier BV; Elsevier
• Subjects: Bayesian analysis; Bayesian calibration; Crystal dislocations; Crystallography; Cylinders; Dislocation; Dislocation density; Dynamic loading; High strain rate; Plate impact tests; Single crystal; Single crystals; Slip resistance; Tantalum; Temperature dependence; Thermomechanical properties; Twinning; Yield strength; Bayesian calibration; Tantalum; Single crystal; Dynamic loading; Dislocation
• ISSN: 0749-6419; 1879-2154
• DOI: 10.1016/j.ijplas.2021.102940

In this work, we extend a dislocation-density based constitutive theory for the dynamic thermomechanical behavior of crystals to body centered cubic (BCC) tantalum. Strain rate and temperature dependence of the slip resistance in the model is incorporated via an expression for the state-dependent instantaneous saturation dislocation density and a dynamic recovery fraction that affects the rate of generation of immobile dislocation density. Crystallographic slip along 111 on the {110} or {112} planes as well as their combination are examined. The Schmid stress serves as the driving force for dislocation motion and the twinning/anti-twinning sense of slip on {112} planes is accounted for by introduction of Peierls stress that depends upon this sense. The model parameters are calibrated using a two-stage Bayesian approach against experimentally generated uniaxial stress-strain compression curves at quasi-static and high strain rates over a range of temperatures. Velocity-time histories from single crystal flyer plate impact experiments were also used to parameterize this model. The calibrated model was applied to simulate previous Taylor cylinder impact experiments. Our results show that the model must include slip on {110} and {112} planes and also account for the twinning versus anti-twinning sense of slip on {112} planes, to appropriately represent the orientation dependence of the flow stress and match the deformed geometry of the single crystal Taylor cylinders. •A dislocation-based constitutive theory is extended to model single crystal tantalum.•Non-Schmid effects are included in model via twin/anti-twin sense of slip on (112).•Uniaxial stress experiments conducted on single crystal tantalum complement previous.•A Bayesian approach is used to calibrate model to large range of experimental data.•The model is validated by comparison to previous Taylor cylinder impact experiments.