606 Influence of grain boundary misorientation angles on dislocation activity in a polycrystalline metal

Dislocation activities in polycrystalline grains depend on their grain boundary (GB) structures such as misorientation angle between two adjacent grains. In order tensile loading are computed based on molecular dynamics (MD) running on 20 cores parallel computers. The computation time reduction as increasing the number of processors is evaluated. As the results, at the GBs with small misorientation angle, dislocations can penetrate easily through them, because the GB function as an obstacle against dislocation movement is less active. On the other hand, at GBs with large angle, penetration is not often observed. According to the strength of each polycrystals, inverse Hall-Petch effect is observed and it corresponds with the former experimental results of this grain size scale. Results also indicates that dislocation activities still remains even in the small grains when inverse Hall-Petch effect is observed.