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Athermal brittle-to-ductile transition in amorphous solids
Olivier Dauchot1, Smarajit Karmakar, Itamar Procaccia
1Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|December 21, 2011
Summary
Researchers introduce an athermal brittle-to-ductile transition, independent of temperature, by altering interparticle potential cutoff length. This explains material behavior and resolves simulation discrepancies in fracture dynamics.
Area of Science:
- Materials Science
- Computational Physics
- Solid Mechanics
Background:
- Brittle materials fracture sharply, while ductile materials deform plastically.
- The brittle-to-ductile transition is typically studied as a function of temperature.
- Previous molecular dynamics simulations showed discrepancies in crack propagation under different boundary conditions.
Purpose of the Study:
- Introduce an athermal brittle-to-ductile transition mechanism.
- Explain ductility onset via plastic modes.
- Resolve the mystery of differing crack behavior in experiments versus simulations.
Main Methods:
- Extensive numerical simulations of material response to constant pulling speed.
- Analysis of brittle-to-ductile transition as a function of interparticle potential cutoff length.
- Investigating the role of plastic modes in material ductility.
Main Results:
- An athermal brittle-to-ductile transition was observed, dependent on potential cutoff length.
- Ductility onset is linked to an increased density of plastic modes with longer cutoff lengths.
- The study clarifies why brittle materials show dynamic cracks in experiments but not always in simulations.
Conclusions:
- The potential cutoff length is a critical parameter for athermal brittle-to-ductile transitions.
- Understanding plastic mode density explains ductility and resolves simulation-experiment discrepancies.
- Distinguishing between brittle and ductile athermal amorphous materials is key to understanding fracture mechanics.
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