| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Understanding and Predicting Dynamic Behavior of Materials
|
| Presentation Title |
Brittle-ductile Failure Transition of Low-symmetry HCP Metal Beryllium under Dynamic Compression |
| Author(s) |
Nitin Daphalapurkar, Darby Luscher, William Blumenthal, Abigail Hunter |
| On-Site Speaker (Planned) |
Nitin Daphalapurkar |
| Abstract Scope |
Uniaxial compression of polycrystalline beryllium (grade S-200F), obtained from quasi-static and split-Hopkinson pressure bar experiments, suggest a significant increase in the failure strain with decreasing rates. In order to predict failure strains, we developed an anisotropic damage model based on A.N. Stroh’s analysis of a crack nucleated by a dislocation pileup. Further, under global compression, the sliding of a Stroh crack induces formation of wing cracks. Kinetic laws for crack growth, dislocation velocity, and dislocation density evolution are physically motivated. Material constants were calibrated using flow stress measurements over a range of strain rates 0.001-5,000 /s. Synergistic with the experimental measurements, we demonstrate the innovative capability of our model to predict trends in the rate-dependence and the temperature-dependence of failure strain. Our model also predicts tension-compression asymmetry and grain-size dependence. Our summary identifies requirements from additional experimental measurements for validation of micromechanical models employed in the proposed theory. |
| Proceedings Inclusion? |
Undecided |