About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
|
Symposium
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Mechanical Behavior at the Nanoscale VI
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Presentation Title |
On the Nanoscale Mechanics of Basal Dislocations in MAX Phases: Atomistic Modeling of Structure and Mobility |
Author(s) |
Gabriel Plummer, Christopher Weinberger, Michel Barsoum, Garritt J. Tucker |
On-Site Speaker (Planned) |
Garritt J. Tucker |
Abstract Scope |
MAX phases, a large family of layered ternary carbides and nitrides, some of which are quite oxidation and creep resistant while also being machinable and damage tolerant. While these properties are advantageous for applications such as structural components in extreme environments, the mechanistic origins of their deformation remain relatively unknown. Newly developed interatomic potentials enable atomistic calculations of dislocation structure and mechanics. Results indicate the key role of intralayer bonding, with weak bonds favoring non-planar cores and reduced mobility. Basal dislocations also preferentially arrange as same-signed pairs on adjacent slip planes. The mobility of these pairs approaches that of dislocations in metals, a result of greater core spreading. Basal dislocations appear to be key precursors to other deformation mechanisms, such as ripplocations, kinking and delamination. These findings provide a solid foundation for further understanding MAX phase plasticity and opportunities to better engineer their deformation behavior, especially at higher temperatures. |
Proceedings Inclusion? |
Planned: |
Keywords |
Computational Materials Science & Engineering, Mechanical Properties, Ceramics |