Hydrogen embrittlement (HE) in a specific sense meaning can be defined as the hydrogen-caused deterioration of the mechanical properties of most metallic materials and alloys. The coexistence of different HE mechanisms and their simultaneous effects in metallic materials, including steels, is still not well documented, while recognition of the dominant mechanism, one or more, is an extremely challenging and crucial problem. A special structural integrity model was proposed [1] for analysis, prevention, and prediction of HE based on the HELP + HEDE model [2] for HE in steels. The structural integrity model corresponds with the observed coexistence of HE mechanisms (HELP + HEDE model) in metals and transition from HELP dominance to HEDE dominance at a hydrogen concentration above the critical hydrogen concentration [2,3]. The further implementation of methods for evaluation, control, and prevention of hydrogen-assisted mechanical degradation processes and HE in metals requires that the variables relevant to the application be incorporated into the basic concept that define all necessary successive steps (5-step approach) for the industrial application [2]. The global 5-step approach in assessment and prevention of hydrogen assisted mechanical degradation processes and hydrogen embrittlement in metals for the practical industrial application was proposed and consist of the following steps [3]: (1) phenomenology analysis of hydrogen-related degradation (multiscale modeling and simulation of HE phenomena); (2) hydrogen sources and entry into metal/component; (3) structural integrity (SiM) model and (4) predictive maintenance (PdM) model which should provide the basis for future (5) reliable and accurate HE damage prediction of different industrial components.

[1] M.B. Djukic, G.M. Bakic, V. Sijacki Zeravcic, A. Sedmak, B. Rajicic, Hydrogen embrittlement of industrial components: prediction, prevention, and models, Corrosion, 72 (2016), pp. 943-961.

[2] M.B. Djukic, V. Sijacki Zeravcic, G.M. Bakic, A. Sedmak, B. Rajicic, Hydrogen damage of steels: A case study and hydrogen embrittlement model, Engineering Failure Analysis, 58 (2015), pp. 485-498.

[3] M.B. Djukic, V. Sijacki Zeravcic, G.M. Bakic, A. Sedmak, B. Rajicic, The synergistic action and interplay of hydrogen embrittlement mechanisms in steels and iron: Localized plasticity and decohesion, Engineering Fracture Mechanics 216 (2019), p. 106528.