The temperature dependence of cyclic dynamic recrystallization in as-extruded pure zinc

Abstract

The deformation characteristics of as-extruded pure zinc were studied over a wide deformation temperature range from −40 °C to 300 °C. Two-cycle dynamic recrystallization was recognized for the first time to occur at different temperatures, leading to an oscillatory flow curve. The second stress peak was mitigated as the deformation temperature increased, while it disappeared at 300 °C. Different mechanisms, including twin dynamic recrystallization, twin-assisted grain boundary nucleation, and continuous mechanism were operative during the first dynamic recrystallization cycle, while the discontinuous mechanism was dominant during the second cycle. The accelerated dynamic recovery at high temperatures (200 °C) exhausted the driving force for the occurrence of the second dynamic recrystallization cycle. A distinct difference was observed between the microstructure developed at high and low temperatures. A bimodal recrystallized grains microstructure was formed at 25 °C, while a deformed microstructure including elongated grains was developed at 200 °C. Increasing the deformation temperature from 25 °C to 200 °C remarkably increased the grain orientation spread values and strengthened the final texture intensity, where the maximum texture intensity was remarkably increased from 9.95 to 30.64 multiple of a random distribution.

Keywords

• Pure zinc
• Deformation behavior
• Dynamic recrystallization
• Texture