The objective of the present study was to find the orientation relationship between a recrystallized grain at its initial stage and a deformation microstructure in a non-uniformly deformed copper single crystal.
   A tensile strain of 25% was applied to a 〈110〉 copper single crystal sample in which shallow grooves were made at both side faces before the tensile test to promote non-uniform deformation. A thin disc specimen prepared from the deformed sample was annealed in a high vacuum. A scanning electron microscope (SEM)/electron backscatter diffraction (EBSD) method was used to analyze the orientations of deformed and annealed states.
   There are two primary slip planes of the largest Schmid factor in a face-centered-cubic metal single crystal deformed along a 〈110〉 direction. In the present copper single crystal sample, both right-up and right-down band-like regions are formed in which either of the primary slips was activated. The arrangement of band-like regions on the overall sample surface was almost symmetrical. Between band-like regions, there were regions of patchy slip appearance, consisting of double-slip and single-slip areas. The band-like regions were rotated so that the slip directions moved towards the tensile axis. On the other hand, the rotation of patchy regions was relatively small.
   In the disc specimen annealed at 833 K, a recrystallized region was formed at the boundary between band-like and patchy regions. The recrystallized region consisted of two types of recrystallized grains having a twin relationship each other. Both types of recrystallized grains had an 〈111〉-rotated orientation relationship with the band-like region.