Cyclic deformation behavior of [001] isoaxial copper tricrystals, bicrystals and single crystals

The cyclic deformation behavior of [001] isoaxial copper tricrystals as wel l as bicrystals and single crystals was studied. It was found that the cycl ic hardening curves of tricrystals, bicrystals and single crystals did almo st overlap at the initial rapid hardening period. The difference between th em was not obvious even at the saturation period. Cyclic stress-strain (CSS ) curves of bicrystals were higher than that of single crystals. The CSS cu rve of tricrystals was located between them. There were no effect zones in the vicinity of grain boundaries and triple junctions according to the obse rvation of dislocation microstructures. The strengthening effects of grain boundaries and triple junction lines on axial stress of specimens were almo st negligible owing to the formation of Lomer-Cottrell locks caused by the reaction of dislocations on different slip planes.