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.