EFFECT OF DEFORMATION TWINNING ON THE FLOW STRESS OF ROLLING-TEXTURED PURE TITANIUM

摘要

This study aims to investigate the effects of deformation twinning on the strain hardening behavior of rolling-textured pure titanium. Uniaxial compression tests in normal direction (ND), rolling direction (RD), and transverse direction (TD) were conducted up to 20% of strain to analyze the flow behavior in relation to the deformation twinning. The strain hardening rate of TD was the lowest due to the lowest twinning activity, while that of RD was the highest owing to grain refinement effect and texture hardening caused by {10-12} tensile twinning. The effect of grain refinement in ND was almost balanced by texture softening of {11-22} compression twinning, which leads to the lowest flow stress increment. Hardening by deformation twinning resulted from the decrease of dislocation pile-up by twinning-accornmodated strain. Finally, Schmid factor analysis was conducted to quantify the effect of lattice reorientation in the twinned regions.