Thermal effects in dislocation theory. II. Shear banding
1Department of Physics, University of California, Santa Barbara, Santa Barbara, California 93106-9530, USA.
Physical Review. E
|February 18, 2017
Summary
Thermodynamic dislocation theory explains shear-banding instabilities using effective configurational temperature and plastic strain rate. High sensitivity to stress and temperature drives rapid shear banding and yielding transitions.
Area of Science:
- Materials Science
- Thermodynamics
- Solid Mechanics
Background:
- Shear-banding instabilities are critical phenomena in material deformation.
- Understanding the underlying mechanisms of plastic strain rate is essential for predicting material behavior.
Purpose of the Study:
- To describe shear-banding instabilities using thermodynamic dislocation theory.
- To investigate the role of effective configurational temperature and plastic strain rate in material instabilities.
Main Methods:
- Utilized thermodynamic dislocation theory.
- Employed a formula for plastic strain rate based on thermally activated depinning of dislocations.
- Analyzed the sensitivity of plastic strain rate to stress and ordinary temperature.
Main Results:
- The system exhibits rapid shear banding instabilities when thermal relaxation is slow.
- Demonstrated extreme sensitivity of plastic strain rate to stress and temperature variations.
- Observed rapid transitions from elastic to plastic behavior at yielding points.
Conclusions:
- Thermodynamic dislocation theory provides a robust framework for understanding shear banding.
- The sensitivity of plastic strain rate is a key factor driving material instabilities.
- The theory successfully predicts yielding transitions and shear banding phenomena.
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