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

Hot deformation behavior of beta-quenched Zr-1Nb was studied by constructing a processing map in the temperature range of 600-950 degrees 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 degrees C and at strain rates slower than 0.1 s(-1) (predominantly in the alpha phase) with a peak strain rate sensitivity of 0.24 occurring at 730 degrees C and 10(-3) s(-1), and the second domain of dynamic recovery occurring in the beta phase field with its peak strain rate sensitivity of 0.22 at 950 degrees 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 beta phase was the thermally activated breaking of attractive junctions. (C) 2013 Elsevier B.V. All rights reserved.