About this Abstract |
Meeting |
2024 TMS Annual Meeting & Exhibition
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Symposium
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Computational Discovery and Design of Materials
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Presentation Title |
Large-scale Ab-Initio Computation of Core Energetics of Pyramidal Dislocations in Mg and Mg-Y Alloy Using DFT-FE: Implications Towards Ductility Enhancement |
Author(s) |
Sambit Das, Vikram Gavini |
On-Site Speaker (Planned) |
Sambit Das |
Abstract Scope |
Recent work (Science 359, 447-452 (2018)) suggests a pyramidal <c+a> screw dislocation cross-slip based mechanism to significantly enhance the low ductility of magnesium through dilute solution alloying. The key inputs to the associated mechanistic ductility model are the pyramidal dislocation core and dislocation-solute interaction energetics. In this talk, I will present the application of DFT-FE to accurately compute these quantities for the first time, requiring cell sizes reaching 6,000 atoms (60,000 electrons). Subsequently, I will discuss how the above first-principles inputs are incorporated into an improved mechanistic model of the cross-slip activation barrier, that includes the missing physics of influence of non-glide stresses on the core energetics, and solute strengthening effects. Finally, I will demonstrate that significant influence of the above aspects on the predicted cross-slip barrier and provide quantitative predictions of Y concentration ranges where cross-slip occurs at a much faster rate leading to enhanced ductility in Mg-Y alloy. |
Proceedings Inclusion? |
Planned: |
Keywords |
Magnesium, Modeling and Simulation, Mechanical Properties |