Effects of yttrium addition on microstructural evolution and recrystallization mechanisms in commercial pure titanium during thermomechanical processing

• Y 2 O 3 particles refine grains and weaken texture by adjusting recrystallization and pinning. • Y 2 O 3 particles promote continuous dynamic recrystallization via developing substructures. • Y 2 O 3 particles enable continuous static recrystallization by providing nucleation sites. • Slip-driven deformation texture evolution and its inheritance effect are clarified. To meet the stringent microstructural requirements of cathode rollers for manufacturing ultra-thin electrolytic copper foil, this study investigates the effect of yttrium (Y) addition on grain refinement and texture evolution in commercial pure titanium (CP-Ti) during thermomechanical processing. With 0.1 wt% Y addition, finely dispersed Y 2 O 3 particles with a cubic bixbyite structure form in the as-cast microstructure, effectively refining prior β grains and restricting the growth of α lamellae. During hot working, Y 2 O 3 particles pin grain boundaries, suppressing grain coarsening and promoting continuous dynamic recrystallization, which reduces the average hot-rolled grain size from 36.56 μm to 23.09 μm and weakens the basal texture. In cold deformation, Y 2 O 3 particles facilitate the formation of lamellar dislocation cells and micro-shear bands, activating twinning and pyramidal slip, thereby further weakening deformation texture. Upon annealing, subgrain nucleation in high-dislocation-density zones and particle-stimulated nucleation at Y 2 O 3 particles lead to continuous static recrystallization, resulting in a refined fully recrystallized grain size of 2.48 μm compared to 4.01 μm in CP-Ti, along with significant weakening of the recrystallization texture. This work systematically elucidates the role of Y in governing microstructure and texture throughout thermomechanical processing of CP-Ti.