The dynamic restoration behavior of 99.99% polycrystalline aluminum was investigated. The deformation was carried out by compression test at 533773 K and initial strain rate of 0.0022 s-1 to a true strain of （1.0） f...The dynamic restoration behavior of 99.99% polycrystalline aluminum was investigated. The deformation was carried out by compression test at 533773 K and initial strain rate of 0.0022 s-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.展开更多
In order to describe and predict the kinetic process of discontinuous dynamic recrystallization （DDRX） during hot workingfor metals with low to medium stacking fault energies quantitatively, a new physically-based m...In order to describe and predict the kinetic process of discontinuous dynamic recrystallization （DDRX） during hot workingfor metals with low to medium stacking fault energies quantitatively, a new physically-based model was proposed by considering thecharacteristics of grain size distribution, capillary effect of initial grain boundaries （GBs） and continuous consumption of GBs. UsingIncoloy 028 alloy as a model system, experiments aiming to provide kinetic data （e.g., the size and volume fraction of recrystallizedgrain） and the associated microstructure were performed. Good agreement is obtained between model predictions and experimentalresults, regarding flow stress, recrystallized fraction and grain size evolution. On this basis, a thermo-kinetic relationship upon thegrowth of recrystallized grain was elucidated, i.e., with increasing thermodynamic driving force, the activation energy barrierdecreases.展开更多
基金Project (G1999064908) supported by the National Key Fundamental Research & Development Program of China
文摘The dynamic restoration behavior of 99.99% polycrystalline aluminum was investigated. The deformation was carried out by compression test at 533773 K and initial strain rate of 0.0022 s-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.
基金Project(51431008)supported by the National Natural Science Foundation of ChinaProjects(2017YFB0703001,2017YFB0305100)supported by the National Key Research and Development Program of China
文摘In order to describe and predict the kinetic process of discontinuous dynamic recrystallization （DDRX） during hot workingfor metals with low to medium stacking fault energies quantitatively, a new physically-based model was proposed by considering thecharacteristics of grain size distribution, capillary effect of initial grain boundaries （GBs） and continuous consumption of GBs. UsingIncoloy 028 alloy as a model system, experiments aiming to provide kinetic data （e.g., the size and volume fraction of recrystallizedgrain） and the associated microstructure were performed. Good agreement is obtained between model predictions and experimentalresults, regarding flow stress, recrystallized fraction and grain size evolution. On this basis, a thermo-kinetic relationship upon thegrowth of recrystallized grain was elucidated, i.e., with increasing thermodynamic driving force, the activation energy barrierdecreases.
