Temperature Dependence of Embrittlement of Cu[001] Symmetrical Tilt Boundaries Induced by Bi Segregation

Cu bicrystals with various [001] symmetric tilt boundaries doped with Bi were tensile tested at several temperatures. The fracture behavior depended strongly on the misorientation angle, Bi doping time, aging conditions and testing temperature. Grain boundaries were more embrittled with increase in the Bi doping time and by the aging treatment depending on misorientation. As the testing temperature increases, the difference in the degree of embrittlement among different grain boundaries became more significant. These observations could be understood reasonably by considering the grain-boundary energy. The grain boundaries are more brittle and fracture more easily at lower tensile stresses with increasing grain-boundary energy.