Characterization of hot deformation behavior of Zr–1Nb–1Sn alloy

Abstract

The hot deformation behavior of β-quenched Zr–1Nb–1Sn was studied in the temperature range 650–1050 °C and strain rate range 0.001–100 s −1 using processing maps. These maps revealed three different domains: a domain of dynamic recovery at temperatures <700 °C and at strain rates <3 × 10 −3 s −1, a domain of dynamic recrystallization in the temperature range 750–950 °C and at strain rates <10 −2 s −1 with a peak at 910 °C and 10 −3 s −1 (in α + β phase field), and a domain of large-grain superplasticity in the β phase field at strain rates <10 −2 s −1. In order to identify the rate controlling mechanisms involved in these domains, kinetic analysis was carried out to determine the various activation parameters. In addition, the processing maps showed a regime of flow instability spanning both α + β and β phase fields. The hot deformation behavior of Zr–1Nb–1Sn was compared with that of Zr, Zr–2.5Nb and Zircaloy-2 to bring out the effects of alloy additions.