Microscopic characterization of hydrogen-induced quasi-brittle fatigue fracture in low-strength carbon steel

The microscopic feature of hydrogen-induced quasi-brittle fatigue fracture in low-strength carbon steel was investigated by transmission electron microscopy and electron backscatter diffraction These analyses, aided also by fractography, explicitly revealed the following points, i) brittle striation is formed by extensive slip at the crack tip, ii) quasi-brittle facet is not crystallographically related to the (100) cleavage plane, and iii) crack growth process is stable These results may suggest that the crack growth, despite its brittle appearance, is essentially a combined process of extensive slip and significantly localized ductile cracking, which is distinct from the normal slip-off growth mechanism (C) 2010 Elsevier B V All rights reserved