Effect of orientation and purity on the dynamic recrystallization of aluminum single crystals with multi glide systems

Abstract

The effects of crystal orientations and purities on the dynamic recrystallization of aluminum were investigated using constant-compression-speed testing. Three multiple-glide-orientation single crystals ([111], [100], and [110] of 99.999 mass% purity) were compressed in the temperature range from 413 to 653 K. Regular multipeak stress oscillations were generated in the three orientations above 453 K. The [111] single crystals showed a primary peak stress at the lowest strain, and the highest work hardening rate up to the primary peak stress. The effect of purities were also investigated using [111] single crystals during 533 K compression tests. Regular multipeak stress oscillations were generated in 99.999 and 99.9999 mass% aluminum while a monotonous work hardening occurred in 99.99 mass% aluminum. The comparison test using [111] single crystals with different Si content revealed that a regular multipeak stress oscillation was generated in 2 mass ppm Si while a monotonous work hardening occurred in 25 mass ppm Si. These observations demonstrated that the dynamic recrystallization of pure aluminum is controlled not only by the accumulation rate of the strain energy but also by the grain boundary mobility restricted by trace impurities.