Abstract:The effects of channel segregation on the macro- and micro-scale chemical composition, microstructure, hardness, and tensile deformation behavior of Ti45Nb wires were investigated. The results show that wires with severe channel segregation exhibit a macroscopic chemical composition identical to those without segregation, and 3D X-ray imaging result also reveals no abnormalities. After annealing, both types of wires exhibit an equiaxed single-phase microstructure with comparable grain sizes, suggesting that channel segregation has negligible influence on the macroscopic composition and grain size. Metallographic examination reveals that channel segregation manifests as spot-like features in the transverse section and band-like structures in the longitudinal section. EDS analysis identifies these regions as Ti-enriched segregations, with a Ti content higher than that of the surrounding matrix by approximately 4.42wt%. Compared to segregation-free wires, those containing extensive channel segregation demonstrate a 15.5% increase in ultimate tensile strength and a 12.3% increase in yield strength, but suffer a reduction in elongation and reduction of area by 19.8% and 18.9%, respectively. Furthermore, the mechanical properties of wires with segregation show significant fluctuations. Fractographic analysis reveals a larger fracture surface area in segregated wires. Severe dislocation pile-ups occur at the interfaces of these segregated regions, initiating microcrack nucleation. This promotes rapid crack propagation of the Ti45Nb wire, leading to a significant decrease in plasticity and reduction of area.