Hot deformation behavior of Zr-1Nb alloy: Characterization by processing map

Hot deformation behavior of β-quenched Zr-1Nb was studied by constructing a processing map in the temperature range of 600-950 °C and strain rate range 0.002-10 s−1. The processing map exhibited a domain of dynamic recrystallization in the temperatures range 625-800 °C and at strain rates slower than 0.1 s−1 (predominantly in the α phase) with a peak strain rate sensitivity of 0.24 occurring at 730 °C and 10−3 s−1, and the second domain of dynamic recovery occurring in the β phase field with its peak strain rate sensitivity of 0.22 at 950 °C and 0.1 s−1. These domains were identified on the basis of detailed kinetic analysis, reported values of ductility and observation of deformed microstructure. While cross-slip was identified to be the dominant rate controlling mechanism during dynamic recrystallization, the rate controlling dislocation mechanism involved in dynamic recovery of the β phase was the thermally activated breaking of attractive junctions.