Development of an interatomic potential for the simulation of defects, plasticity, and phase transformations in
M I Mendelev1, T L Underwood2, G J Ackland3
1Division of Materials Sciences and Engineering, Ames Laboratory, Ames, Iowa 50011, USA.
The Journal of Chemical Physics
|October 27, 2016
Summary
New interatomic potentials for titanium (Ti) accurately model phase transitions and defects. Researchers developed specific potentials for low and high temperatures, enabling simulations of titanium
Area of Science:
- Materials Science
- Computational Physics
- Chemical Engineering
Background:
- Developing accurate interatomic potentials is crucial for simulating material properties.
- Titanium (Ti) exhibits complex behavior, including phase transitions and defects, necessitating specialized potentials.
Purpose of the Study:
- To develop and validate new interatomic potentials for titanium (Ti) that describe defects, plasticity, and high-temperature phase transitions.
- To accurately determine the martensitic hexagonal close-packed (hcp) to body-centered cubic (bcc) phase transformation temperature in Ti.
Main Methods:
- Employed molecular dynamics (MD) based on determining melting temperatures of competing solid phases.
- Utilized Gibbs-Helmholtz integration and a lattice-switch Monte Carlo (MC) method.
- Developed embedded atom method (EAM) potentials, including Ti1, Ti2, and Ti3, and a combined temperature-dependent potential.
Main Results:
- Achieved agreement on hcp-bcc transformation temperatures within 2 K using different methods.
- Developed Ti1 potential that reproduces hcp-bcc transformation and melting temperatures, suitable for simulating phase transitions and bcc Ti.
- Developed Ti2 and Ti3 potentials that accurately describe defect properties for simulating plasticity or radiation damage in hcp Ti.
Conclusions:
- A single EAM potential cannot accurately describe both low and high-temperature phases of Ti, potentially due to neglected electronic entropy.
- A combined, temperature-dependent potential (Ti1 + Ti2) can simulate Ti properties across a wide temperature range.
- The developed potentials provide valuable tools for computational materials science research on titanium.
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