Suppression of ambient-temperature creep in CP-Ti by cold-rolling

The suppressing effect of ambient-temperature creep of CP-Ti by cold-rolling was reported. Annealed plates of CP-Ti grade 2 were cold-rolled with thickness reductions, and then creep tests under the applied stresses of 0.6–0.9σ0.2 were performed at ambient temperature. With increasing the thickness reduction, the twin, dislocation density and σ0.2 were found to increase. At the same time, the steady-state creep rates under the applied stress for constant σ/σ0.2 were decreased. The cold-rolled sample with 20% thickness reduction was then annealed at 813 K for 2400 s to decrease only the dislocation density. After the annealing, the steady-state creep rate remained constant, suggesting that the reduction of the steady-state creep is associated with the increasing twin density.