Dynamic embrittlement-time-dependent brittle fracture

Dynamic embrittlement (DE) is a generic type of brittle intergranular fracture where the crack propagation is controlled by grain boundary diffusion of an embrittling element, which can come from the material itself, e.g., during S-induced stress relief cracking of steels, or from the surrounding atmosphere, e.g., hold-time cracking of Ni-base superalloys. Four-point bend tests on poly- and bicrystalline specimens revealed that cracking by dynamic embrittlement depends strongly on local microstructural features, e.g., the grain-boundary structure. (C) 2004 Elsevier B.V. All rights reserved.