Effects of initial orientation on microstructure evolution of aluminum single crystals during hot deformation

Abstract

The predominant crystallographic relations between dynamic recrystallization (DRX) nuclei and simple deformation structures have been characterized in aluminum single crystals (ASCs) of Cube{001}<100> and S{123}<634> orientations. Electron backscattered diffraction (EBSD) and electron channeling contrast imaging (ECCI) measurements revealed that the DRX behavior of ASCs dependent on initial grain orientation. The diverse distributions of slip systems and stress-axis orientations in Cube- and S-orientation ASCs contribute to the difference in initial slip system, DRX behavior and misorientation accumulation. The Cube-orientation ASCs are predominated by microbands at (25–300 °C)/(0.001–10 s−1), only a few discontinuous dynamic recrystallized (DDRX) grains are found at 300 °C/(0.001–10 s−1). While the DRXs behaviors in S-orientation ASCs are significantly under 300 °C/(0.001–10 s−1). DDRX grains in S-orientation ASCs reach millimeter level even at 25 °C/10 s−1. Many continuous dynamic recrystallized (CDRX) grains and sub-grain structures are found at 300 °C/10 s−1. Misorientation angles across DRX interfaces are grouped in the range of 20°–50° (with a maximum at 30°–40°) around axes located near the normal of {111} planes.