English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Plasticity in hexagonal close packed (HCP) metals and alloys such as Titanium(Ti) and Zirconium (Zr) is carried out by the motion of $\langle a \rangle$dislocations. Above room temperature, in situ transmission electron microscopystraining experiments have shown that basal slip of $\langle a \rangle$ screwdislocations in Ti is activated and its preponderance increases withtemperature. To discern the mechanism of basal slip of these dislocations inpure Ti, molecular dynamics (MD) simulations and nudged elastic band (NEB)calculations were performed for a screw dislocation gliding on the basal plane.From MD simulations, basal and pyramidal slip were shown to be intertwined. Thescrew dislocation glides by kink pair nucleation and propagation mechanism onone of the two equiprobable pyramidal planes adjacent to the maximum resolvedshear stress basal plane, before switching to the other pyramidal plane, thusleading to an average basal slip at low stress and/or high temperature. On theother hand, NEB calculations revealed that at low stresses kinks do notnucleate in the pyramidal plane but rather directly in the basal plane fullycompatible with the motion of a screw dislocation confined to the basal plane,in agreement with experimental observations in Ti and Zr. The discrepancybetween these two mechanisms is shown to be related to the thermal activationof the cross-slip from the pyramidal to the prismatic core configuration of the$\langle a \rangle$ screw dislocation.

Characteristics of $\langle a \rangle$ Screw Dislocations Basal Slip in Titanium