Ab initio reappraisal of the dislocation-associated stacking faults in hcp titanium: a new dissociation mechanism

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The slip is a secondary slip system in hexagonal close-packed metals which is often activated when they undergo a c-axis deformation. The behaviour of the screw dislocation remains unclear. Via ab initio calculations with an all atom all direction relaxation method, we find a stable 0.57 stacking fault on plane () and a stable nanotwinned 0.215 stacking fault on plane () in -Ti. Based on these results, we propose a screw dislocation dissociation mechanism which allows a split to three partials. This suggests a more complex screw dislocation-related cross-slip mechanism.