Understanding the texture evolution and deformation mechanism of Zr-2.5Nb alloy during cold rolling

Zirconium (Zr) alloy is widely used in the nuclear industry due to its low thermal neutron absorption cross-section and excellent mechanical properties. The texture easily formed in the hcp-structured α-Zr determines its service performance. To analyze the texture evolution and deformation mechanism during cold rolling, the Zr-2.5Nb alloy was rolled to various reductions in two directions (rolling direction (RD) and transverse direction (TD)) at two deformation temperatures (room temperature (RT) and cryogenic temperature (CT)). A combined approach of experimental observation and crystal plasticity simulation was employed to systematically investigate the texture evolution and deformation mechanism under cold rolling. The TD-spread elliptical texture is formed in α-Zr during RD-rolling, while the disc-shaped basal texture is produced during TD-rolling. The prismatic slip has no effect on the texture type. The basal slip leads to the formation of strong basal texture. The pyramidal <c+a> slip causes the basal poles to tilt toward RD. Both prismatic and basal slips lead to the formation of the TD-spread elliptical texture with double peaks. At RT, the final FND of RD-rolling is similar to that of TD-rolling, a similarity that is caused by basal slip. The Kearns factors of normal direction (ND) is recorded as FND. At CT, {10 1‾ 2} and {112‾ 1} twinning play an important role in the early stage of deformation. Compared to TD-rolling at RT, the relatively inactive basal slip results in lower texture intensity during TD-rolling at CT. This study deepens our understanding of the texture evolution and deformation mechanisms of Zr alloy.