Abstract
A phase-field model is developed to simulate the hardening effect of sessile loops (vacancy and interstitial discs) resulted from neutron irradiation in tungsten. According to experimental observations, the gliding dislocations on the {1 1 0} prism planes and the Burgers vector is 1/2 < 1 1 1 >, while the sessile damage loops are perpendicular to the slip plane and the Burgers vector is same with gliding dislocation. It is found that the size and spatial distribution of the damage loops as well as their amount have strong impact on their hindrance to dislocation glide. The increases in the number density and radius of damage loops enhance the hardening effect. As the edge dislocation glides through the top and bottom of the damage loop, the hardening effect is more pronounced than that in other cross section. With same stress field, the edge dislocation gliding through the bottom of damage loop requires higher critical resolved shear stress than that through the top of the damage loop, due to the sequential change in the force direction. The stress fields of two loops along < 1 1 0 > direction cancel out each other to some extent. Hence the hardening effect increases with increasing distance between the two loops.
NSTL
Elsevier