Prismatic edge dislocations in graphite

Abstract

Dislocations are a central concept in materials science, which dictate the plastic deformation and damage evolution in materials. Layered materials such as graphite admit two general types of interlayer dislocations: basal and prismatic dislocations, of which prismatic dislocations have been relatively less studied. Using density functional theory (DFT) calculations, we have examined different prismatic core structures in graphite and evaluated their structure, energetics and mobility. We find close energetic interplay between bonded and “free-standing” core structures in both zigzag and armchair directions, with a reconstructed stable zigzag core identified. We explore grain boundaries and prismatic dislocation pile-up, identifying metastable structures which may be important in energy storage. The role of interlayer stacking in core structure, dislocation glide and climb is also considered in-depth. Our calculations suggest that the prismatic dislocation core is stable up to high temperatures of approximately 1500 K in bulk graphite. Above this temperature, the breaking of bonds in the dislocation core can facilitate climb, grain-boundary motion, and the annealing of damage through prismatic dislocation glide. © 2021 Elsevier LtdANR-20-CE08-0026, TUBITAK-2219; Engineering and Physical Sciences Research Council, EPSRC: EP/P020232/1, EP/R005745/1This work was supported by the United Kingdom EPSRC grant EP/R005745/1 , Mechanisms of Retention and Transport of Fission Products in Virgin and Irradiated Nuclear Graphite. Kenny Jolley and Pavlos Mouratidis also gratefully acknowledge funds from EDF energy generation 2016–2021 . The authors gratefully acknowledge the use of Athena at HPC Midlands+, which was funded by the EPSRC grant EP/P020232/1 as part of the HPC Midlands + consortium. CE and AI acknowledge ANR-16-CE24-0008-01 “EdgeFiller” and ANR-20-CE08-0026 “OPIFCat” for funding. DE acknowledges support from the TUBITAK-2219 post-doctoral research abroad fund.This work was supported by the United Kingdom EPSRC grant EP/R005745/1, Mechanisms of Retention and Transport of Fission Products in Virgin and Irradiated Nuclear Graphite. Kenny Jolley and Pavlos Mouratidis also gratefully acknowledge funds from EDF energy generation 2016?2021. The authors gratefully acknowledge the use of Athena at HPC Midlands+, which was funded by the EPSRC grant EP/P020232/1 as part of the HPC Midlands + consortium. CE and AI acknowledge ANR-16-CE24-0008-01 ?EdgeFiller? and ANR-20-CE08-0026 ?OPIFCat? for funding. DE acknowledges support from the TUBITAK-2219 post-doctoral research abroad fund