On the influence of ageing on the onset of plastic slip in Ti-6Al-4V at room temperature: Insight on dwell fatigue behavior

Two different metallurgical states of Ti-6Al-4V have been used to assess the influence of ordering and Ti3Al precipitation on its deformation behavior at room temperature. In-situ tensile tests performed inside a scanning electron microscope coupled with slip trace analysis enabled to identify the operating deformation systems at the onset of plastic slip. The differing macroscopic behavior is due to a significant influence of ordering and Ti3Al precipitation on the activation chronology of the slip systems. Indeed, basal and prismatic critical resolved shear stresses are found unequally changed with ageing. Potential insights on the dwell behavior of titanium alloys are discussed. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.