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Published on: May 15, 2017
Irreversibility transition of colloidal polycrystals under cyclic deformation
Pritam Kumar Jana1, Mikko J Alava1, Stefano Zapperi1,2,3,4
1COMP Centre of Excellence, Department of Applied Physics, Aalto University, P.O.Box 11100, FI-00076 Aalto, Espoo, Finland.
Scientific Reports
|March 31, 2017
Summary
Disordered particle systems transition to irreversibility under cyclic loading. This study reveals dislocation-driven irreversible behavior in colloidal polycrystals, showing enhanced diffusion and strain bursts at the transition.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Statistical Mechanics
Background:
- Disordered particle systems, including granular materials and amorphous media, exhibit a non-equilibrium phase transition to irreversible behavior under cyclic loading.
- Understanding this transition is crucial for predicting material behavior under dynamic conditions.
Purpose of the Study:
- To numerically investigate the cyclic deformation of a colloidal polycrystal containing impurities.
- To identify the mechanisms driving the transition to irreversible behavior in such systems.
- To draw parallels between amorphous and polycrystalline material deformation.
Main Methods:
- Numerical simulations of cyclically loaded colloidal polycrystals with impurities.
- Analysis of particle displacement and dislocation motion.
- Investigation of system size effects and strain burst distributions.
Main Results:
- A transition to irreversible behavior was observed, driven by dislocation displacement.
- Enhanced particle diffusion, system size effects, and broadly distributed strain bursts characterize the phase transition.
- An analogy was established between the deformation of amorphous and polycrystalline materials.
Conclusions:
- Dislocation dynamics play a key role in the irreversible deformation of colloidal polycrystals.
- Zener pinning of grain boundaries can be reinterpreted as a mechanism to inhibit irreversible crystal ordering.
- The findings offer insights into the fundamental physics of disordered materials and crystal plasticity.
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