This work systematically investigates the microstructure evolution, texture transformation, deformation mechanism, and tensile response of Ti-2Al-2. 5Zr tubes during multi-pass cold rolling using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), and in-situ tensile testing. The novelty of this study lies in correlating rolling-pass-dependent microstructure and texture evolution with cooperative slip/twinning deformation behavior and mechanical property changes in small-diameter thick-walled titanium alloy tubes. With increasing rolling passes, the α-grain morphology evolves from relatively equiaxed to elongated/fragmented bands, accompanied by an overall refinement of the α microstructure. The Schmid-factor analysis indicates an enhanced tendency for prismatic slip, whereas basal slip remains nearly unchanged, and a small amount of 10-12 tensile twinning is observed to assist local strain accommodation. Meanwhile, the maximum α-texture intensity shows an overall decrease at high deformation. Tensile testing demonstrates a clear strengthening effect: yield strength (YS) increases from 453. 7 MPa to 562. 1 MPa, and ultimate tensile strength (UTS) increases from 686. 9 MPa to 755. 1 MPa, while the ductility exhibits a slight reduction. These results reveal that strengthening is mainly associated with dislocation accumulation and microstructure refinement, whereas the retained ductility is related to coordinated slip/twinning deformation and texture dispersion.
Wang et al. (Sun,) studied this question.