Effect of heating rate on the recrystallization behavior and mechanical properties of a cold-rolled Zr702

With the aim of investigating the influence of heating rate on the recrystallization behavior and mechanical properties of Zr702, a Zr702 sheet with a basal texture was cold rolled up to 70% reduction at room temperature. Then, the deformed samples were heat-treated with three heating rates (5, 10 and 50 °C/s) up to four target temperatures (600, 650, 700 and 750 °C) following by quenching in water. Microstructures of the heat-treated samples were characterized by backscatter electron and electron backscatter diffraction (EBSD) techniques. Compression tests were carried out to reveal the mechanical properties of the heat-treated Zr702. Results indicate that no obvious recrystallization takes place at 600 °C for all heating rates. At temperatures from 650 to 750 °C, for a given heating rate or temperature, the fraction and average grain size of recrystallized grain both increase with increasing temperature or decreasing heating rate. Except a weakened basal texture observed in the samples heat-treated at heating rates of 5 and 10 °C/s up to 750 °C, the textures for the other heat-treated samples do not significantly change compared to the deformed sample. The compressive yield strength of the heat-treated sample decreases with the increase of temperature or the decrease of heating rate when heating rate or temperature remains constant. Moreover, the strength calculations based on the EBSD data reveal that dislocation strengthening results in higher strength for the samples heat-treated at low temperatures or highest heating rate.