The Dislocation Network Evolution under Irradiation Conditions in Dislocation Dynamics Simulations
Dan Mordehai (Technion), Emmanuel Clouet (CEA), Laurent Dupuy (CEA)
Discrete Dislocation Plasticity
Tue 9:00 - 10:30
RI Hall 108
In crystalline metals, the dislocation network is the main source of internal strain. Irradiation steadily injects vacancies and interstitials, which diffuse into the existing microstructure and as a consequence, the evolution of the dislocation network is driven by irradiation. Examples are irradiation enhanced dislocation annealing, irradiation driven re-crystallization and irradiation induced plasticity at temperatures and stress levels where plastic strain does not show up in the absence of irradiation. Dislocation climb has been recently incorporated in Dislocation Dynamics (DD) simulations, by coupling this technique with the diffusion theory of point defect. We extend the model so as to describe irradiation dislocation climb and the alteration of climb by the existing dislocation microstructure. The influence of the internal strain arising from the dislocation network is taken into account in the diffusion flux of point defects (vacancies and interstitials) into each dislocation segment. This allows us to incorporate coordinated climb mechanism in DD simulations. Simulations demonstrate the coarsening of dislocation loops in bulk annealing conditions and the importance of coordinated climb to the disappearance of dislocation loops. These results suggest that both vacancies and interstitials contribute to the recovery of the initial dislocation microstructure under irradiation.