X-ray Diffraction Technique for Analysing Failed Components

摘要

General criterions for determination of the local stress state at the crack tip of the material under different types of loading conditions such as: ⅰ) static, ⅱ) impact, ⅲ) high-speed impulse, ⅳ) impact-cyclic, ⅴ) cyclic are proposed. They are the ratio of the maximum depth plastic zone to the specimen thickness (h_(max)/t) and the ratio of the diffraction line width obtained from the fracture surface to the diffraction line width obtained from the unstrained metal (β/β_0). The plane strain deformation condition under static and cyclic loading conditions may be defined more precisely using by above criterions. X-ray techniques for determination: ⅰ) material fracture toughness of the failed construction, ⅱ) critical fatigue crack length l_s and l_f, ⅲ) stress of the loading cycle, ⅳ) load ratio R, ⅴ) track growth speed are presented. If the fracture surface was completely damaged by corrosion or mechanical affect, X-ray techniques may be used for identification of the type of the fracture surface.