Evolution of microstructure and mechanical properties influenced by nanosized precipitates during rolling deformation

Abstract

In this research work, the 6111Al reinforced by rare earth element Er was subjected to severe plastic deformation with different rolling reduction ranging from 50%, 70%–90% respectively. Continuous deepening of the dynamic recrystallization occurred during the increment on rolling deformation and the average size of α-Al grains decreased to 7.9 μm eventually. The nanosized Al3Er particles were characterized by the combined function of inhibiting and promoting the DRX at the same time during the rolling process. And the competitive relationship between the driving force and the restraining force has been studied via systematic calculation here. A noticeable enhancement on 6111Al–Er alloy has been obtained with YS, UTS and elongation increasing to 359 MPa, 380 MPa and 27.4% respectively when the rolling deformation reached to 90%, which was attributed to the synergistic strengthening effect induced by the fine grain strengthening and the Orowan strengthening mechanisms. The evolution of microstructure was characterized by the equipments including Electron backscattered diffraction (EBSD), Scanning electron microscope (SEM) and High resolution transmission electron microscope (HRTEM).