Effect of Al3Zr particles on hot-compression behavior and processing map for Al-Cu-Li based alloys at elevated temperatures

The influence of Al3Zr particles on the hot compression behavior and processing map (PM) of Al-Cu-Li based alloys under isothermal plane-strain compression in the temperature range of 400-500 degrees C and at the strain rates of 0.01-10 s(-1) was investigated. The corresponding microstructure was analyzed using optical microscopy (OM), electron back-scattered diffraction (EBSD) and transmission electron microscope (ULM). The results showed that dynamic recovery (DRV) played a greater role than dynamic recrystallization (DRX) in dynamic softening. At low temperatures, the Al3Zr particles were the significant barriers to inhibit DRV and DRX grain growth. When the temperature reached 500 degrees C, the Al3Zr particles readily spread along grain boundaries just like a necklace due to the dissolution of Al3Zr particles and rapid diffusion of Zr through grain boundary, resulting in generating the macroscopic cracks and forming an instability domain at 490-500 degrees C, 0.01 s(-1) in the PM.