Hydrogen embrittlement examples

Hydrogen has a low solubility in solvents for example, at ambient conditions, only 0.018 and 0.078 mL of gaseous H2 dissolves into each milliliter of water and ethanol, respectively. However, the solubility is much more pronounced in metals. Palladium is particularly notable in this respect, which dissolves about 1000 times its volume of the gas. The adsorption of hydrogen in steel may cause "hydrogen embrittlement," which sometimes leads to the failure of chemical processing equipment [4],... 

A-2.8.1 Pressure and Temperature. An important general trend is that structural metals become more susceptible to hydrogen embrittlement as hydrogen gas pressure increases. An example of this trend is the measured threshold stress intensity factor, Km, as a function of gas pressure for low-alloy steels. Kjh decreases as gas pressure increases. Increasing hydrogen gas pressure enhances the concentration of dissolved hydrogen in materials, which promotes hydrogen embrittlement. 

Hydrogen embrittlement typically occurs below 95°C (200°F), because hydrogen remains dissolved within the steel at or below this temperature. One example of hydrogen embrittlement is underbead cracking. The... 

The content of this chapter is closely related to permeation, which is the transport of a solute across a layer of solvent (or membrane) under the action of a difference in activity. For example, the permeation of hydrogen through a metal foil has been studied, particularly for palladium [F.A. Lewis (1967)] and iron [J. P. Hirth (1980) H. H. Johnson (1988)]. One reason for studying the permeation of hydrogen through iron is to understand the hydrogen embrittlement of steel. 

If local stresses exceed the forces of cohesion between atoms or lattice molecules, the crystal cracks. Micro- and macrocracks have a pronounced influence on the course of chemical reactions. We mention three different examples of technical importance for illustration. 1) The spallation of metal oxide layers during the high temperature corrosion of metals, 2) hydrogen embrittlement of steel, and 3) transformation hardening of ceramic materials based on energy consuming phase transformations in the dilated zone of an advancing crack tip. 

The EAM and MEAM potentials once determined from electronics principles calculations [178] have been used to reproduce physical properties of many metals, defects, and impurities. For example, EAM molecular statics, molecular dynamics, and Monte Carlo simulations were performed on hydrogen embrittlement effects on dislocation motion and plasticity [46,179-181]. These potentials have been used to analyze plasticity [74,144,145,148-150,182,183], cracks and fracture [117,184], and fatigue [119, 120, 185, 186]. 

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