Statistical model for diffusion-mediated recovery of dislocation and point defect microstructure

Statistical model for diffusion-mediated recovery of dislocation and point defect microstructure

Statistical model for diffusion-mediated recovery of dislocation and point defect microstructure 150 150 UKAEA Opendata
UKAEA-CCFE-PR(18)25

Statistical model for diffusion-mediated recovery of dislocation and point defect microstructure

The evolution of the defect microstructure in materials at high temperature is dominated by diffusion-mediated interactions between dislocations, vacancy clusters and surfaces. This gives rise to complex non-linear couplings between interstitial and vacancy-type dislocation loops, cavities and the field of diffusing vacancies that adiabatically follows the evolution of microstructure. We expand a formalism for the climb of curved dislocations to include the population of very small defects and dislocation loops that are below the experimental detection limit. These are taken into account through a mean field approach coupled with an explicit real-space treatment of discrete defect clusters. We find that randomly distributed small defects screen diffusive interactions between larger discrete clusters, renormalizing the free diffusion Green’s functions and transforming them into Yukawa-type propagators. The evolution of the coupled system is modelled self-consistently, showing how the defect microstructure evolves through a non-monotonic variation of the distribution of sizes of dislocation loops and cavities, treated as discrete real-space objects.

Collection:
Journals
Journal:
Physical Review B
Publisher:
APS