recently, grave explosions in the oil and gas transport tubes, as well as, the rapid failure of the machine parts in service, were caused by hydrogen cracking. during solidification of metals, in casting ,welding, cathodic charging, etc., the hydrogen can enter in metals and cause premature cracking. the hydrogen embrittlement in metals is accompanied with a charge in the type of fracture surfa...

Slow strain rate tests were performed on quenched and tempered AISI 4340 steel to measure the extent of hydrogen embrittlement caused by electroplating with zinc-cobalt alloys. The effects of bath composition and pH were studied and compared with results for electrodeposited cadmium and zinc-10%nickel. It was found that Zinc-1%cobalt alloy coatings caused serious hydrogen embrittlement (EI 0.63...

Calculations indicate that the introduction of hydrogen into the body–centred cubic and face-centred cubic allotropes of iron in both cases reduces the {100} surface energy. The reduction is rather small in magnitude so this mechanism cannot present the major cause of the well–known hydrogen embrittlement phenomenon. Consistent with the theory of grain boundary embrittlement in iron, carbon is ...

While hydrogen embrittlement of ferritic steels has been a subject of significant research, one of the major challenges in tackling hydrogen embrittlement is that the mechanism of embrittlement is not fully resolved. This paper reports new observations and interpretation of fracture surface features and deformation microstructures underneath the fracture surface, providing a mechanistic view of...

The feasibility of using ‘‘grain-boundary engineering” techniques to reduce the susceptibility of a metallic material to intergranular embrittlement in the presence of hydrogen is examined. Using thermomechanical processing, the fraction of ‘‘special” grain boundaries was increased from 46% to 75% (by length) in commercially pure nickel samples. In the presence of hydrogen concentrations betwee...

In this study, the hydrogen transport phenomenon was numerically evaluated by using hydrogen-enhanced localized plasticity (HELP) mechanisms. Two dominant governing equations, namely, the hydrogen transport model and the elasto-plastic model, were introduced. In addition, the implicitly formulated equations of the governing equations were implemented into ABAQUS UMAT user-defined subroutines. T...