The deformation of metals is closely related to its microstructure. When a metal is subjected to an external force, the atoms within it rearrange, leading to deformation. In traditional coarse-grained metals, dislocation motion is the primary deformation mechanism. However, when the grain size is reduced to the nanoscale, grain boundary sliding (GBS) becomes the dominant factor.
Methods
To delve deeper into GBS in nanometal deformation, H. Van Swygenhoven and P. M. Derlet from the Paul Scherrer Institute in Switzerland employed molecular dynamics simulations. They constructed a nickel nanocrystal model with an average grain size of 12 nanometers and simulated its deformation process under tensile loading.
Highlights
Revealed the atomic mechanism of grain boundary sliding: The study found that grain boundary sliding is mainly achieved through two atomic processes: atomic shuffling and stress-assisted free volume migration.
Discovered the regulation process of grain boundary sliding: Under high stress and room temperature conditions, grain boundary and triple junction migration, as well as dislocation activity, play a crucial role in regulating grain boundary sliding.
This research provides atomic-level insights into the deformation mechanisms of nanometals. These findings will contribute to the design and development of novel nanometallic materials with superior mechanical properties.
Fig. 1. A section of the GB between grains 1 and 14. Displacement vectors are shown indicating the change in position between two levels of strain during plastic deformation. Atomic shuffling between the grains can be observed.
Fig. 2. A view detailing the nature of the twin-plane migration within the grain boundary at a total strain of 1.7% and 3%
Authors
This work was conducted by Prof. H. Van Swygenhoven and Prof. P. M. Derlet from the Paul Scherrer Institute in Switzerland.
H. Van Swygenhoven, P. Derlet, Grain-boundary sliding in nanocrystalline fcc metals, Physical review B 64(22) (2001) 224105. DOI: https://doi.org/10.1103/PhysRevB.64.224105
To advance the research of GBS, researchers are encouraged to include strain and GBS displacement data in their publications.
Editor: Dr. Jun-Jing He
