Study on recrystallization and correlated mechanical properties in Mo-modified Zr-Nb alloys

The recrystallization behaviors and correlated mechanical properties in Mo-modified Zr-Nb alloys were systematically investigated in this study. Electron backscatter diffraction, transmission electron microscopy and universal tensile tests were employed to characterize the recrystallization behaviors and evaluate their mechanical properties. Results showed that doping of Mo greatly retarded the recrystallization process and significantly reduced the grain size in Zr-Nb alloys. Bimodal basal texture was observed in these specimens, and an increase of Mo content weakened the intensity of normal basal texture. Both the Zener pinning effect of precipitates and dragging effect of solute atoms enhanced by doping of Mo are responsible for the retarded recrystallization. The calculation of grain size was further performed by applying Zener equation, it shows that not only the precipitates but also the preexistent strains influence the recrystallized grain size. In addition, Mo addition enhanced the yield strength, however reduced the ductility. The strengthening contributions from solute atoms, grain boundaries and precipitates were calculated based on the microstructural parameters. The calculation reveals that grain size strengthening is the greatest contributor in Mo-modified Zr-Nb alloys.