Dresden 2026 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 7: Mechanical Properties and Alloy Design II
MM 7.4: Talk
Monday, March 9, 2026, 16:30–16:45, SCH/A215
Jog-Pair Formation and Climb Mechanisms of Dissociated Dislocations in FCC Metals — •Erik Bitzek1, Sergei Starikov2, and Daria Smirnova1,2 — 1Max Planck Institute for Sustainable Materials, Düsseldorf, Germany — 2ICAMS, Ruhr-Universität Bochum, Germany
Jogs on dislocations are preferred sites for vacancy segregation and thus play a critical role in dislocation climb. Under conditions of high point-defect supersaturation – such as after quenching or irradiation – the availability of jogs along the dislocation line can become the rate-limiting factor for climb. Understanding jog-pair nucleation is therefore essential for modeling the kinetics of dislocation creep. Jog pair formation on split edge dislocations in fcc metals was first investigated by Thomson and Balluffi [J. Appl. Phys. 1962] and atomistic simulations [Sarkar et al., PRB 2012] confirmed the suggested mechanism. However, both studies assumed a certain vacancy configuration at the dislocation as the initial nucleus.
Using high-temperature molecular dynamics simulations of dislocations in vacancy supersaturated nickel, we identify an alternative pathway that takes place without predefined nuclei. We demonstrate the role of ⟨ 110⟩-oriented vacancy tubes in the climb of edge and 60∘ dislocations and propose a new climb mechanism for 30∘ dislocations involving double cross-slip of the screw partial dislocation. These findings highlight how atomistic simulations can inform mesoscale models of creep and annealing.
Keywords: dislocation climb; creep; vacancy diffusion; high-temperature materials; molecular dynamics simulations