Yuanbo Bi, Yuying Li
To reveal the high-temperature hot deformation mechanism and optimize the thermal processing window of Zr-Nb alloy, hot compression tests were implemented via a thermal simulation apparatus over temperatures ranging from 500 to 900 °C and strain rates of 0.01~10 s-1. The material's flow performance, dynamic recrystallization (DRX) and phase transformation were systematically explored in this work. The results indicate that flow stress presents a negative correlation with deformation temperature and a positive correlation with strain rate. On the basis of measured stress-strain curves, the Arrhenius constitutive equation and processing map were established to quantitatively describe the alloy's hot deformation behavior. Flow instability areas are mainly distributed in the low-temperature domain and the high strain rate region of medium-high temperature zones. The evolution of DRX under different strain rates and microstructural variations during phase transformation was analyzed in detail. Elevated strain rate leads to gradual grain refinement. Continuous dynamic recrystallization (CDRX) acts as the predominant DRX mode for Zr-Nb alloy, with merely minor discontinuous dynamic recrystallization (DDRX) features observed in the microstructure.