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Micromechanics of emergent patterns in plastic flows
Santidan Biswas1, Martin Grant, Indradev Samajdar
1Department of Physics, Indian Institute of Technology, Bombay, Powai, Mumbai-400 076, India.
Scientific Reports
|September 24, 2013
Summary
Plastic deformation in polycrystalline solids exhibits complex atomic displacements, revealing localized patterns indicative of crystal structure. Understanding these behaviors is crucial for material science and geophysics.
Area of Science:
- Materials Science
- Solid Mechanics
- Computational Physics
Background:
- Crystalline solids deform plastically and flow under stress exceeding their elastic limit.
- Polycrystalline solids, common in nature, are crucial for applications ranging from material processing to earthquake dynamics.
- Simulating plastic flow in these materials requires understanding phenomena across multiple scales.
Purpose of the Study:
- To investigate the spatio-temporal heterogeneity of atomic displacement fields in sheared polycrystalline solids.
- To identify microscopic signatures of crystallinity within the plastic deformation process.
- To determine the necessity of multi-scale modeling for describing polycrystalline solid mechanics.
Main Methods:
- Utilizing the phase field crystal (PFC) model for simulation.
- Analyzing atomic displacement fields under shear stress.
- Comparing simulation results with characteristics of amorphous solids and single crystals.
Main Results:
- Observed spatio-temporal heterogeneity in atomic displacement fields across multiple length and time scales.
- Identified localized quadrupolar patterns, signifying the interaction of dislocations.
- Demonstrated that polycrystals exhibit characteristics of both amorphous and crystalline solids.
Conclusions:
- Plastic flow in polycrystalline solids is characterized by complex, heterogeneous atomic displacements.
- The phase field crystal model reveals microscopic signatures of crystallinity, such as dislocation interactions.
- Accurate modeling of polycrystalline solids necessitates integrating continuum plastic flow and discrete dislocation dynamics.
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