Effect of Initial Orientation on Microstructural Evolution of Aluminum Single Crystals During Hot Deformation

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. The ASCs were uniaxial compression at different temperatures (25, 300 ℃) and strain rates (0.001, 10 s−1). The deformed ASCs were analyzed using electron backscattered diffraction (EBSD) and electron channeling contrast imaging (ECCI). Local orientation measurements implied that Cube-oriented ASCs are dominated by a group of microbands, while DRXs in S-oriented ASCs are significant. There are few discontinuous dynamic recrystallized (DDRX) grains in Cube-oriented ASCs, while DDRX grains in S-oriented ASC reach a millimeter level at 25 ℃/10 s−1. Many continuous dynamic recrystallized (CDRX) grains and sub-grain structures are observed in S-oriented ASCs at 300 ℃/10 s−1. Misorientation angles across the DRX interfaces are grouped in the range of 20–50° (with a maximum at 30–40°). The diverse distribution of slip systems and stress-axis orientations in differently oriented ASCs contributes to the difference in the initial slip system, misorientation accumulation and DRX behavior.