| In this thesis, we studied the pure aluminum bicrystal system by giving the bicrystal specimens a moderate strain (10%--20%)individually on the Instron machine. The two grains were strained differently due to the different Schmid factor. The specimens were then annealed at 500°C in the furnace for a certain amount of time and cooled in the air. EBSD technique was used to track the grain boundary motion and triple junction formation during the annealing process after the specimens were electropolished.; We observed that various types of boundary motion occurred for different amount of strains. For specimens that were given 20% strain, stable triple junctions were observed at the end of the less-strained grain after a short period of time. In order to track the boundary migration, we strained two specimens for 10% and observed the whole boundary migration process during the aging. In another specimen that was strained 16%, multiple small grains was observed to appear in the more-strained grain at the early stage of annealing and we were able to trace the entire grain growth process.; Several important conclusions can be made after careful analysis on the results of above specimens. Strain-induced grain boundary migration (SIBM) was confirmed to be the dominant mechanism during the recrystallization and the subsequent grain growth and the migration rate could be proportional to the strain energy stored in the adjacent grains. For the specimen that formed a number of small grains in the annealing process, we noticed that the proportion of CSL special boundaries was not changed significantly during annealing, which means gain growth might not be an effective way to increase the number of CSL boundaries in aluminum. Also, study on the grain boundary triple junctions in this specimen showed that the shape of a triple junction was largely affected by the boundary energy of its components. |
