A statistical model of hydrogen-induced fracture of metals

Abstract

The fracture process of metals due to hydrogen embrittlement is described theoretically as a first order phase transition. The fractured and unfractured phases are in equilibrium at the instant of fracture and are described by the equality of stresses and thermodynamic potentials. In the context of this approach, the dependences of the fracture stress on the molar hydrogen concentration and on the fracture deformation are calculated. The dependence on the molar hydrogen concentration turned out to be close to the power depen dence, while the dependence on the fracture deformation is very close to linear. Not only the qualitative but also the quantitative correspondence of this model to the experimental results is shown.

Understanding and mitigating hydrogen embrittlement of steels: a review of experimental, modelling and design progress from atomistic to continuum

“…Indeitsev et al [80] proposed a model for the fracture stress as a function of hydrogen content based on statistical mechanics. They estimated the number of broken chemical bonds produced by hydrogen using Fermi–Dirac statistics, where the energy is equal to the sum of the plastic energy in the absence of hydrogen and the excess energy induced by hydrogen-induced decohesion.…”

Влияние Водорода На Флуктуационное Охрупчивание Алюминия

“…Растворимость водорода в твердом алюминии равна 0.034 ml/100 g при температуре плавления T ∼ 660 • C, поэтому, как правило, оказывается, что атомы водорода собираются вместе. Следовательно, в твердом алюминии начинается процесс образования пор [2], приводящий впоследствии к охрупчиванию и образованию трещин [3][4][5][6][7]. Именно поэтому детальное микроскопическое описание поведения атомов водорода в алюминии является актуальной задачей.…”