Hot Workability of Zr-2.5Nb Alloy: Unveiling Microstructural Evolution and Texture Development Under Compression

A comprehensive study is conducted on the hot workability and microstructural evolution of a Zr-2.5Nb alloy, encompassing deformation temperatures from 700°C to 850°C and strain rates from 0.01 s⁻¹ to 10 s⁻¹. Based on the acquired flow stress data, an Arrhenius constitutive model is formulated and a hot processing map is constructed. Furthermore, we systematically analyze the microstructure and texture of the deformed samples. By integrating these findings, the optimum processing parameters are determined at all strain rates around 800°C, whereas conditions of 700°C and higher strain rates are deemed unstable. In the stability processing region, the c-axis of some grains in the compressed sample deviates from the compression direction (CD) by approximately 90°. Under instability-processing conditions, a texture in which the grain c-axis deviates from the CD by approximately 35° is easily formed. Both continuous dynamic recrystallization (DRX) and discontinuous DRX play are observed in the hot compressed sample. The discontinuous DRX grains play an important role in the weakening of texture. The inhibition of basal slip combined with interaction between the two phases during hot compression causes the grain c-axis to rotate away from the CD.