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Information × Registration Number 0224U000216, 0121U108959 , R & D reports Title Evaluation of physical and mechanical macro- and micromechanisms of action of hydrogen-containing media on the strength and performance of low- and complex-alloy steels popup.stage_title Head Dmytrakh Ihor M., Доктор технічних наук Registration Date 03-01-2024 Organization Physico-Mechanical Institute named after GV Karpenko of the National Academy of Sciences of Ukraine popup.description2  The main result of the work is the development of new approaches to evaluating the mechanisms of hydrogen action on low-alloyed and complex-alloyed steels, which are based on the use of the value of the concentration of hydrogen in the metal as a crucial parameter for the realization of one or another mechanism, which leads to a change in their plasticity characteristics, strength, and resistance to fracture. It is shown, for the first time that the specificity of the mechanism of hydrogen influence (conditional plasticization, embrittlement, or mixed mechanism) on strength characteristics is determined by the ratio of diffusible and residual (trapped) hydrogen in its total amount in low-alloyed steels. The peculiarities of the mechanism of decreasing the yield strength of low-alloy pipe steels under the influence of hydrogen, which at low concentrations (0.3–0.4 ppm) in the metal is diffusible which generates void-like defects on the nano, micro, and macro levels, which facilitate deformation of the material and reduce its resistance to fracture. The realization of such mechanism leads to a formal decrease in the value of the yield strength as a macroscopic characteristic of the material. This effect should be characterized as increased deformability of the material as a result of the specific action of diffusible hydrogen of low concentration, which increases its defectiveness. The basic “resistance to fracture – hydrogen concentration” diagrams were constructed for low-alloy steels in the case of the presence of mechanical stress concentrators and crack-like defects in the material, which make it possible to establish the value of the critical concentration of hydrogen, upon reaching which the local resistance of the material to fracture is significantly reduced. Based on the data obtained using transmission microscopy, it was established that the mechanisms of the influence of hydrogen gas on the strength and cyclic crack resistance of complex alloyed Ni–Co Product Description popup.authors Ivasʹkevych Lyubomyr M. Balytskyi Oleksandr I. Barna Roman A. Gavryluk Mariia R. Hembara Nazar Tarasovych Hrynenko Mykhajlo V. Dmytrakh Ihor Mykolayovych Kolesnikov Valerii O. Leshchak Rostyslav L. Sapuzhak Yaroslav І. Syrotyuk Andriy M Sov'yak Ivanna М. popup.nrat_date 2024-01-03 Close