Cu bicrystals with various [110] symmetric tilt boundaries doped with Bi were tensile tested. Their fracture behavior depended sensitively on the misorientation angle at the boundaries, Bi doping time and aging temperature. A strong correlation between the fracture behavior and grain-boundary energy before the Bi doping has been found: the higher the grain-boundary energy, the easier becomes the brittle fracture at grain boundaries. As the Bi doping time increased, grain-boundary brittle fracture occurred more easily. These phenomena could be explained resonably by considering the boundary-dependent amount of segregation of Bi atoms.
