In situ synchrotron radiation observation of deformation and annealing processes of aluminum single crystal

The objective of the present study is to carry out in situ observations of deformation and annealing of aluminum (Al) single crystals using a synchrotron radiation X-ray at SPring-8. Al single-crystalline samples having a <111> orientation parallel to the longitudinal direction were grown by the Bridgman method. The samples were deformed in tension to a nominal strain of 8% at room temperature using an in-line tensioning apparatus. Post-deformation annealing at 480 ℃ was subsequently carried out in the same apparatus. A two-dimensional detector was used to detect multiple diffracted beams from the sample during deformation and annealing. The volume irradiated by the X-ray beam was found to be composed of three regions having small orientation differences attributable to the subgrain microstructures of the sample. Detailed analyses of diffraction spot intensity showed that the subgrain microstructures were surpassed by dislocated microstructures as the tensile strain increased. During post-deformation annealing, diffraction spots from a recrystallized grain first appeared at 180 s after the temperature reached 480 ℃. The coexistence of diffraction spots from the deformation matrix and recrystallized grains lasted only about 22 s in the irradiated volume. The migration rate of the boundary between the deformation matrix and the recrystallized grain was estimated to be on the order of several micrometers per second. (author)