Investigation of the crystallographic texture and microstructure evolution during thermomechanical processing of a Zr-0.6Nb-0.4Mn alloy

The evolution of crystallographic texture and microstructure in a Zr–0.6Nb–0.4Mn alloy was investigated using an optimized thermomechanical processing route comprising β-solution treatment, limited hot rolling, high cold rolling, and short-time, low-temperature annealing. This route was designed to develop a strong basal texture with poles preferentially aligned with the sheet normal direction in an experimental alloy, a condition known to mitigate deleterious hydride reorientation and improve the in-service performance of zirconium fuel claddings. High cold rolling reduction (81.6%) played a key role in building a pronounced basal texture with the {0001} < 10 1 ¯ 0 > and {0001} < 11 2 ¯ 0 > components, with a basal pole tilt from the normal direction toward the transverse direction of approximately 30° compared with textures reported for conventional Zr Nb alloys. Subsequent annealing at 500 °C for 2 h and 4 h promoted partial recrystallization while preserving a high alignment of basal poles with the normal direction (f ND ≈ 0.46). Transmission electron microscopy revealed a partially recrystallized microstructure consisting of fine grains ranging from 300 nm to 2 μm and Mn₂Nb nanoprecipitates (10–50 nm), showing a more homogeneous distribution after 4 h. By combining texture analysis, Kearns factors, and detailed TEM observations, this study demonstrates that tailored combinations of hot and cold deformation with short-time, low-temperature annealing can simultaneously refine texture and precipitation in Zr–Nb–Mn alloys. The resulting basal texture characteristics and controlled precipitation state provide a microstructural basis for improving the performance of zirconium components in nuclear environments.