Multipass warm/hot rolling of single phase Zircaloy 2: Developments in crystallographic texture and in lattice strain

Zircaloy 2, a cast and hot forged alloy with a Widmanstätten structure, was warm/hot rolled to 40 and 80% reductions at approximate working temperatures of 200, 400, 600 and 800°C. The bulk crystallographic texture had clearly different patterns of developments between 200/400 and 600/800°C deformed structures. The estimated lattice strain, on the other hand, had shown noticeable relative softening and hardening after the respective deformation temperatures of 600 and 800°C. The patterns of macroscopic developments, both in bulk crystallographic texture and in lattice strain, could be explained from the microstructural observations. The difference in bulk crystallographic texture was primarily related to the preferred appearance of recrystallised grains. The 600°C rolled structure was associated with recovery/recrystallisation and a concurrent softening while the effects of a similar softening was suppressed through significant intermetallic precipitations and associated strain localisations in the 800°C rolled material.