Detwinning behavior in commercial pure zirconium during orthogonal re-compression after pre-compression and annealing

Twinning is an important plastic deformation mode for zirconium (Zr) and its alloys. Many researches have been carried out to investigate twinning related issues for Zr alloys. However, few study was reported on the detwinning in Zr alloys. In this work, pre-compression, orthogonal re-compression, and annealing were performed to investigate the deformation behavior of a commercial pure Zr (Zr702). Microstructure and texture evolution during deformation and annealing were examined by quasi-in situ electron backscatter diffraction (EBSD). It was found that {10-12} tensile twins were activated during pre-compression of Zr702 plate along rolling direction, while detwinning rather than secondary tensile twinning occurred when the pre-twinned sample was re-compressed along normal direction. Intermediate annealing between the pre-compression and the re-compression may hinder the subsequent detwinning. Moreover, the hindering effect was enhanced when larger pre-compression and longer annealing time were applied, which may be attributed to the annealing induced solute atoms precipitation and coherency loss of twinning boundary.