Continuous dynamic recrystallization and discontinuous dynamic recrystallization in 99.99% polycrystalline aluminum during hot compression
(1. School of Materials Science and Engineering, Central South University,
Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering,
Ministry of Education, Central South University, Changsha 410083, China)
Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering,
Ministry of Education, Central South University, Changsha 410083, China)
Abstract: The dynamic restoration behavior of 99.99% polycrystalline aluminum was investigated. The deformation was carried out by compression test at 533-773K and initial strain rate of 0.002-2s-1 to a true strain of 1.0 followed by water quench. Polarized optical microscopy and transmission electron microscopy were applied to observe the deformation microstructure. It’s found that discontinuous dynamic recrystallization, which is commonly observed in lower stacking fault energy metals or ultra-high purity aluminum(≥99.999%), occurs when Zenner-Hollomon parameter(Z parameter) is low, but the true stress—strain curve doesn’t accompany stress oscillation. Continuous dynamic recrystallization occurs when Z parameter is intermediate, and only dynamic recovery takes place if Z parameter is high.
Key words: hot deformation; continuous dynamic recrystallization; discontinuous dynamic recrystallization; Zenner-Hollomon parameter