Kink-limited Orowan strengthening explains the brittle to ductile transition of irradiated and unirradiated bcc metals

Abstract

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Hybrid quantum/classical study of hydrogen-decorated screw dislocations in tungsten: Ultrafast pipe diffusion, core reconstruction, and effects on glide mechanism

“…While the screw dislocation glide is well characterized in pure bcc materials [8,9], solutes can have a strong effect on the dislocation properties leading to hardening or softening of the material [10]. In tungsten Ir, Pt, Au, and Hg solute atoms show a strong attraction to screw dislocations resulting in hardening by a pinning mechanism, while Hf, Ta, and Re reduce glide barriers and thus facilitate plastic slip [11].…”

Dislocation spreading and ductile–to-brittle transition in post-irradiated ferritic grains: Investigation of grain size and grain orientation effect by means of 3D dislocation dynamics simulations

“…To the best of the author's knowledge, there is currently no experimental technique enabling direct evaluation of dislocation population mobility, let alone their characteristic, dosedependent evolution. An atomic-scale model has been recently developed, however, explaining the brittle-ductile transition based on isolated dislocation/obstacle interaction cases [72]. This model confirms that defect-induced dislocation mobility evolutions can help revealing/evaluating the brittle-ductile transition evolutions.…”

Incorporation of Obstacle Hardening into Local Approach to Cleavage Fracture to Predict Temperature Effects in the Ductile to Brittle Transition Regime

“…The main factor that determines the outcome in the competition between cleavage fracture and ductile tearing is the ability of the plastic deformation to relieve the applied stresses ahead of a crack. On a microstructural scale, plastic flow in bcc metals is controlled by the thermally activated movement of screw dislocations, which is dependent on a combination of an internal lattice resistance and an interaction between the dislocations and obstacles in the microstructure [ 5 , 6 , 7 ]. A recently published dislocation-obstacle model showed that the activation energy for plastic flow is mainly determined by the kink (which represents a step of atomic dimension in a dislocation line) formation energy [ 7 ].…”

“…On a microstructural scale, plastic flow in bcc metals is controlled by the thermally activated movement of screw dislocations, which is dependent on a combination of an internal lattice resistance and an interaction between the dislocations and obstacles in the microstructure [ 5 , 6 , 7 ]. A recently published dislocation-obstacle model showed that the activation energy for plastic flow is mainly determined by the kink (which represents a step of atomic dimension in a dislocation line) formation energy [ 7 ]. Swinburne and Dudarev [ 7 ] were able to predict the ductile to brittle transition temperature in both unirradiated and irradiated ferritic-martensitic steels, where the irradiated temperature increased up to twice that of the unirradiated material in agreement with multiple experimental data.…”