| About this Abstract |
| Meeting |
Materials Science & Technology 2020
|
| Symposium
|
Micro- and Nano-Mechanical Behavior of Materials
|
| Presentation Title |
Temperature-dependent Intermittent Plasticity of Nb Microcrystals |
| Author(s) |
Quentin Rizzardi, Douglas Stauffer, Jaime Marian, Robert Maass |
| On-Site Speaker (Planned) |
Robert Maass |
| Abstract Scope |
Intermittent microplasticity via dislocation avalanches indicates scale-invariance, which is a paradigm shift away from traditional bulk deformation. Recently, we have developed an experimental method to trace the spatiotemporal dynamics of correlated dislocation activity (dislocation avalanches) in microcrystals (Phys. Rev. Mat. 2 (2018) 120601; Phys. Rev. Mat. 3 (2019) 080601). Here we exploit the temperature sensitive deformation of bcc metals. A marked change of the slip-size distribution is observed in the studied microcrystals, with increasingly small event-sizes dominating with decreasing temperature. This shows how a reduction in thermal energy increasingly suppresses the length-scale of dislocation avalanches, indicating how long-range correlations become gradually limited to the scale of the lattice. Our results further show that the stress-strain response is composed of strain-increments that are either thermally activated or essentially athermal. Temperature-dependent small-scale testing in combination with state-of-the-art discrete dislocation dynamics (DDD) simulations of Nb microcrystals are used to reveal these insights. |