A Study of the Formation of Brittle Cracks in Embrittled Materials by the Effects of Environment

The process of formation of brittle cracks in embrittled materials by the effects of corrosive environment were studied by X-ray diffraction and transmission electron microscopic observations. In the case of stress corrosion tests of austenitic stainless steel, in spite of the small amount of plastic deformation, dislocation density increased under constant low tensile stress and after the half of the life times, many cracks were initiated. The initial states of these cracks are alike to G. P. zone in precipitation reaction. These cracks were also formed in the hydrogen charged steels. It could be considered that the initiation of cracks in the material which is fractured following no large ductile deformation may be done as the process.