Abstract
The interaction of a crack-tip slip band with the grain boundary has been modeled for three cases: the slip band which does not reach the grain boundary, the slip band blocked by the grain boundary, and the slip band propagating to the adjacent grain. The continuously distributed dislocation theory was used to compute the crack-tip opening displacement (CTOD) and the microscopic stress intensity factor. The propagation rate of a short crack growing under the interaction with the grain boundary was discussed under the assumption that the range of CTOD directly determines the crack growth rate. The propagation behavior of a short crack was predicted as a function of the distance between the crack tip and the grain boundary, and of the difficulty of slip propagation to the adjacent grains, as well as of the crack length and stress level.
