Dramatic strain rate sensitivity loss of the prismatic slip in titanium from oxygen doping

Abstract

Although the bulk mechanical properties of materials are critically sensitive towards oxygen doping, the effect of oxygen on single prismatic slip is rarely reported. The current study systematically investigates the mechanical response and deformation mechanism of the <a> prismatic slip in single-crystal Ti micropillars with respect to varying oxygen concentrations. The findings show that the <a> prismatic slip is activated intrinsically regardless of oxygen content, while deformation twinning is evidently suppressed at the high oxygen content. Visible strain hardening behavior for the micropillars at the low oxygen content is witnessed and attributed to the interaction between dislocations and twin/stacking faults. Finally, an anomalous loss of strain rate sensitivity of the <a> prismatic slip in highly oxygen-doped single-crystal Ti micropillars is interestingly observed, which is discussed carefully by correlating it with the metastable mechanical shuffling mechanism of oxygen.