About this Abstract |
| Meeting |
MS&T26: Materials Science & Technology
|
| Symposium
|
Fracture of Steels: New Approaches to Modeling and Experimental Characterization
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| Presentation Title |
Evolution of Nanocrystalline Microstructures in Adiabatic Shear Bands During Dynamic Deformation |
| Author(s) |
Janith C. Wanni, Charles N. Adkins, Raymond Rasmussen, Stephan Yang, Marko Knezevic, Curt A. Bronkhorst, Dan J. Thoma |
| On-Site Speaker (Planned) |
Janith C. Wanni |
| Abstract Scope |
Adiabatic shear bands are narrow regions of intense localized deformation that form under high strain-rate loading and are often associated with nanocrystalline microstructures. Although their formation has been widely studied, quantitative, spatially resolved crystallographic data capturing intermediate stages of shear band evolution remain limited. In this work, interrupted top-hat shear experiments combined with high-resolution, dictionary-indexed electron backscatter diffraction were used to characterize the evolution of grain structure, morphology, texture, and geometrically necessary dislocation density across multiple deformation states. Results show a continuous transformation pathway in which martensitic blocks elongate, develop low-angle boundary substructures (~200–300 nm), and progressively fragment into equiaxed nanograins (~300 nm). This process is accompanied by transient increases in grain aspect ratio and dislocation density, followed by decreases as refinement progresses. The similarity between early-stage substructures and final nanograins supports a subdivision-driven refinement mechanism involving progressive misorientation and rotation during dynamic deformation. |