The relation between activated slip systems and nucleation of Recrystallized Grains (RGs) in many types of deformed 99.99 mass% aluminum single-crystals with and without deformation bands (DBs), and various types of bi-crystals have been studied. It is obtained that (1) below 50% strains RGs are formed mainly due to the <111> rotation recrystallization mechanism and (or) Strain Induced Tilt Boundary Migration (SITBM) absorbing piled-up edge dislocations, and (2) over 50% strains RGs formed due to the SITBM become prominent.