About this Abstract |
Meeting |
2024 TMS Annual Meeting & Exhibition
|
Symposium
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Mechanical Behavior at the Nanoscale VII
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Presentation Title |
Brittle and Ductile Deformations in Uniaxial Compression of Si pillars |
Author(s) |
Boyang Gu, Yang Li, Adrian Diaz, David McDowell, Youping Chen |
On-Site Speaker (Planned) |
Boyang Gu |
Abstract Scope |
In this talk, we present a multiscale study, using the Concurrent Atomistic-Continuum (CAC) method, to investigate the mechanism for the brittle and ductile deformation behaviors of Si pillars observed in experiments. The CAC simulations have captured the nucleation, motion, and reaction of dislocations, as well as the formation of a central crack. We find that the buckling of pillars with small diameters promotes single slip, resulting in ductile deformation of the pillars. Conversely, larger-diameter pillars exhibit the intersection of perfect 60° dislocations on two slip planes, leading to the formation of Lomer locks. Sequential pileups of perfect 60° dislocations against the locks initiate the central crack, leading to a brittle failure of the pillars. The CAC method captures the nucleation, motion and the interaction of cracks and dislocations simultaneously without any empirical assumptions. The mechanism underlying the size dependent ductile-brittle transition observed in micropillars is thus clearly demonstrated and illustrated. |
Proceedings Inclusion? |
Planned: |
Keywords |
Modeling and Simulation, Mechanical Properties, |