Deformation banding and static recrystallization in high-strain-rate-torsioned Al-Mg alloy

Abstract

Via applying torsion tests at various strain rates, we investigate the formation of deformation bands during cold deformation and static recrystallization post the subsequent annealing of Al-Mg alloy. High-strain-rate deformations exhibit noticeable variations: high flow stress at low strains, high Schmid factor, and accelerated SRX upon subsequent annealing. We determine that the variations originate from strongly formed DBs in the high-strain-rate deformed sample. Strain analysis based on electron backscatter diffraction and convolutional multiple whole profile methods indicate that most DBs exhibit strain accumulation near their boundaries, which can accelerate SRX upon annealing. In addition, some DBs with low dislocation densities remain in the annealed workpieces. The DBs share the <111> rotation axis with the parent crystal and are generally visible in the shear-plane-normal//<111>-oriented crystal. Consequently, coincidence lattice site boundaries sharing the <111> rotation axis are observed in strain-free DBs.