| About this Abstract |
| Meeting |
MS&T24: Materials Science & Technology
|
| Symposium
|
Fracture in Metals: Insights from Experiments and Modeling Across Length and Time Scales
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| Presentation Title |
Ductility and Brittle Fracture of Tungsten: The Role of Twin Boundaries and Pre-Existing Dislocations |
| Author(s) |
Omar Marwan Hussein, Nicolas Bertin, Tomas Oppelstrup, Fadi Abdeljawad, Timofey Frolov |
| On-Site Speaker (Planned) |
Timofey Frolov |
| Abstract Scope |
Tungsten has been identified as a promising candidate material for fusion applications, but its intrinsic brittle behavior remains a critical challenge. In this work, we use large-scale molecular dynamics simulations of single-crystal tungsten pillars with sizes approaching the micron scale to investigate ductility and fracture as a function of initial defect microstructure, deformation conditions and temperature. Our EAM model of tungsten is seen to be ductile at all temperatures as long as dislocations are present and twin boundaries are absent, while fracture occurs when twins exist or nucleate after dislocation starvation by surfaces. Analysis of fracture events reveals a novel mechanism by which cracks nucleate at low macroscopic stresses at incoherent twin-surface intersections. The ductile stage can be extended by increasing the initial dislocation density, which delays dislocation starvation and twin nucleation. The ductile to brittle transition temperature in our simulations is marked by the disappearance of the TB pinning. |