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 0.6-0.9σ_0.2 were performed at ambient temperature. With increasing the thickness reduction, the twin, dislocation density and σ_0.2 were found to increase. At the same time, the steady-state creep rates under the applied stress for constant σ/σ_0.2 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.