Strain Rate Effect on Dynamic Nucleation at Triple Junctions in a Copper Tricrystal

抄録

Effect of strain rate on dynamic recrystallization (DRX) at triple junction (TJ) in a copper tricrystal was investigated in tension during high-temperature deformation at 873 K. DRX nucleation appeared preferentially at the TJ at around a strain about 2/3 of the peak strain and became easier with decreasing strain rate. The preferential DRX nucleation observed at TJ seemed to have close relationship with occurrence of grain-boundary sliding (GBS). That is, easier occurrence of GBS at lower strain rate can cause more severe stress and deformation concentration at TJ, followed by operation of stimulated DRX nucleation at TJ. The effect of grain boundary misorientation composing the TJ on DRX nucleation at the TJ and its mechanism is also discussed in detail.