Antimony-induced embrittlement of [011] symmetric tilt boundaries in copper bicrystals

Abstract

Copper bicrystals with different [011] symmetric tilt boundaries doped with Sb were tensile tested at several temperatures from 77 to 773 K. The fracture behavior was sensitive to the misorientation angle, Sb doping time, and test temperature. Grain boundaries were more embrittled with increasing the Sb doping time, though their tendency was also dependent on the misorientation angle. The degree of embrittlement of grain boundaries became lower as the test temperature increased to about 500 K, while it became higher again at higher temperatures. The segregation of Sb at [011] tilt boundaries also was systematically measured by energy-dispersive X-ray spectroscopy. A strong correlation was found among the fracture behavior at 77 and 773 K, grain-boundary segregation level of Sb, and grain-boundary energy before Sb doping: a higher-energy boundary has a higher level of Sb segregation and fractures more easily at a lower tensile stress.