Quantitative analysis of grain refinement in titanium during equal channel angular pressing

Strain-driven grain subdivision of commercial pure titanium during 1–8 passes of equal channel angular pressing (ECAP) at 723 K is investigated quantitatively by electron backscattering diffraction. The grain refinement mainly takes place in the first pass and the efficiency gradually decreases from 1 to 4 passes, reaching saturation with further increasing strain (6–8 passes). {1 0 1¯ 2} tensile twins are firstly observed in the first pass of ECAP. Misorientation gradients and the driving force of dynamic recrystallization are discussed.

Research highlights
► Grain refinement in titanium during ECAP from 1 to 8 passes at 723 K is analyzed quantitatively.
► Grain refinement of titanium during ECAP at 723 K mainly takes place in the first pass.
► {1 0 1¯ 2} tensile twins are firstly observed in the first pass of ECAP.
► Misorientation gradients and the driving force of dynamic recrystallization are discussed.