Shear-coupled grain boundary migration assisted by unusual atomic shuffling
Liang-Liang Niu1,2, Ying Zhang1, Xiaolin Shu1
1Department of Physics, Beihang University, Beijing 100191, China.
Scientific Reports
|March 25, 2016
Summary
Shear-coupled grain boundary (GB) migration aids plastic deformation in small-grained materials. Atomistic simulations reveal atomic shuffling assists this process in bcc W, impacting material design.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Computational Materials Science
Background:
- Shear-coupled grain boundary (GB) migration is crucial for plastic deformation in nanocrystalline materials.
- The atomic mechanisms governing GB motion, particularly shear-coupled migration (SCM), remain incompletely understood.
Purpose of the Study:
- To elucidate the atomic-level mechanisms of SCM in bcc Tungsten (W) using atomistic simulations.
- To investigate the influence of GB character on SCM pathways and associated shear strengths.
Main Methods:
- Atomistic simulations were employed to study SCM in symmetrical tilt GBs in bcc W.
- Analysis focused on dislocation slipping modes and atomic shuffling along the tilt axis.
Main Results:
- SCM in bcc W proceeds via dislocation slipping in either <100> or <110> modes, with significant differences in shear strength.
- An unusual atomic shuffling mechanism along the tilt axis was identified, facilitating easier SCM in the <110> mode.
Conclusions:
- GB character plays a critical role in dictating the atomistic mechanisms of SCM.
- Understanding these mechanisms is vital for the future design of high-performance materials through GB engineering.
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