DOI: https://dx.doi.org/10.24866/2227-6858/2019-3-4

Lepov V., Arkhangelskaya E., Achikasova V.

VALERY LEPOV, Doctor of Engineering Sciences, Chief Researcher, Fracture Modeling Department, ORCID 0000-0003-2360-7983, e-mail: lepov@iptpn.ysn.ru
VALENTINA ACHIKASOVA, Lead Engineer, Fracture Modeling Department, e-mail: achikasova@iptpn.ysn.ru
Larionov Institute of Physical and Technical Problems of the North SB RAS
1 Octyabrskaya St., Yakutsk, Russia, 677890
EKATERINA ARKHANGELSKAYA, Candidate of Engineering Sciences, Associate Professor, Department of Expert appraisal, management and cadastre of Real Estate, Engineering and Technical Institute, ORCID 0000-0002-6130-0539, e-mail: ea.arkhangelskaia@s-vfu.ru
M.K. Ammosov North-Eastern Federal University
58 Belinskogo St., Yakutsk, Russia, 677029

Influence of hydrogen on the brittle fracture kinetics in metals

Abstract: A short review of actual researches on damage accumulation modeling and brittle fracture processes mechanisms under the combined effect of mechanical loading and hydrogen has been presented in the article. The modified mechanism of brittle fracture for metallic materials based on dislocation and phonon structure fingerprints and lattice hydrogen content under the static and dynamic loading at low temperature condition has been ground by experimental and numerical studies. The experiment includes the energy spectrum of internal friction determination and impact toughness testing for low-temperature brittle-ductile transition revealing. The numerical study based on damage accumulation modeling under the influence of up-hill diffusion in the elastic-plastic problem of solid state by finite element method. The new simple activation model of low temperature and hydrogen influence on damage accumulation process has been proposed. The tentative calculations show the strong dependence of the rate of damage on stress level and hydrogen content, and on test temperature. The combination of low temperature and high hydrogen content is most dangerous, so the weld structures using in extreme environment like the Arctic and Subarctic regions have high risk of breakage. It is possible to numerically estimate the energy and phonon spectrum of crystal lattice, and predict the properties of microcrystalline and nanostructured materials with high cold-short threshold on the base of such the approach. The recommendations to improve the cold resistance of steels and alloys by controlling the characteristics of the dislocation structure has been given also.
Keywords: damage, modeling, cold resistance, low temperature ductile-brittle transition, fluctuations, lattice hydrogen, dislocation, risk of breakage, cold-short threshold.

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