Logo image
Back
On ripplocations and the deformation of graphite
Journal article   Open access   Peer reviewed

On ripplocations and the deformation of graphite

Hussein O. Badr and Michel W. Barsoum
Carbon (New York), v 201, pp 599-615
05 Jan 2023
DOI: https://doi.org/10.1016/j.carbon.2022.09.042
url
https://doi.org/10.1016/j.carbon.2022.09.042View
Published, Version of Record (VoR)Open Access (License Unspecified),  Open

Abstract

Chemistry Chemistry, Physical Materials Science Materials Science, Multidisciplinary Physical Sciences Science & Technology Technology
The micromechanism for the deformation of layered crystalline solids (LCSs) such as graphite, mica, and the MAX phases has long been assumed to be basal dislocations alone. The latter, however, cannot explain several important observations made when graphite is deformed such as non-linear elasticity, the stress-strain curves' strong sensitivity to confining hydrostatic pressures, evidence for c-axis strain, among other observations. In 2015, the term ripplocation-best described as an atomic layer ripple-was coined and since then we have been making the case that atomic layers in LCSs - like any other layered systems - buckle. Using molecular dynamics simulations on graphite we showed that buckling leads to the nucleation of multiple, oppositely signed ripplocation boundaries (RBs) that rapidly propagate, wavelike, into the bulk to form standing waves. It is the to-andfro motion of RBs and the associated friction between the layers that accounts for the energy dissipation observed when LCS/graphite are cyclically loaded. We also make the case that RBs are not atomically sharp and can be precursors of kink boundaries, KBs. The difference between the two is fundamental: RBs, if not pinned, are fully reversible because they are highly elastically strained. KBs are irreversible and their energy is in the boundary itself. We show that the hallmarks of deformation by ripplocations are: i) nano-ligaments observed in transmission electron microscope microgrpahs; ii) large pileups around spherical indentations when the layers are indented along the c-axis and delamination cracks when they are indented edge-on, and iii) fully reversible hysteretic stress-strain curves.

Metrics

9 Record Views
23 citations in Web of Science
20 citations in Scopus

Details

InCites Highlights

Data related to this publication, from InCites Benchmarking & Analytics tool:

Web of Science research areas
Chemistry, Physical
Materials Science, Multidisciplinary
Logo image