In crystalline metals, the dislocation network was the main source of internal strain, while irradiation steadily injects new sources of internal strain (point defects, defect clusters). As a consequence, the evolution of the dislocation network was driven by irradiation. While the atomistic mechanisms by which the forcing proceeds had long been suggested, namely the partitioning of defect elimination between dislocations and other defect sinks, both in stationary or transient regimes, some of the macroscopic consequences, such as irradiation-enhanced dislocation annealing and irradiation-driven recrystallization, were left unexplained. It was shown here that dislocation-sink strengths for point defects were altered in the presence of neighbouring dislocations and that their climb motion was coordinated with the dislocation microstructure. A climb model, which took account of the dislocation network, provided the mechanism for coordinated climb, which was shown to ease dislocation annealing. In particular, it was demonstrated that coordinated dislocation climb accelerated the annihilation of dislocation pairs of opposite sign and the repulsion of dislocations of the same sign. This, among other things, promoted the annealing of small-angle tilt boundaries by sub-grain rotation.

Enhanced Annealing of the Dislocation Network Under Irradiation. D.Mordehai, G.Martin: Physical Review B, 2011, 84[1], 014115