Damage Accumulation and Recovery Involving Vacancy-Type Defects Enhanced by Hydrogen in Tempered Martensitic Steel Showing Quasi-Cleavage Fracture

Abstract:

Hydrogen embrittlement (HE) is increasingly becoming a critical issue for using high-strength steels in the automotive and infrastructure industries. To overcome the risk posed by HE of structural components under a hydrogen uptake environment in long-term service, it is necessary to clarify the mechanism of HE. In the present study, the presence of hydrogen-enhanced strain-induced vacancies (HESIVs)—one type of defect associated with proposed HE mechanisms—was validated by low-strain-rate tensile tests with in-situ electrochemical hydrogen charging for tempered martensitic steel showing quasi-cleavage fracture with a tensile strength. The effect HESIVs on the mechanical properties of tempered martensitic steel was also studied. The combined use of low-temperature thermal desorption spectroscopy and tensile tests led to the following observations: (i) hydrogen enhanced the accumulation of vacancy-type defects under plastic strain, (ii) accumulated vacancy-type defects adversely affected the ductility of the tempered martensitic steel after hydrogen release, and (iii) aging at 150 °C after applying a given plastic strain with hydrogen charging decreased the amount of newly formed vacancy-type defects and resulted in recovery of ductility.

• Periodical: Key Engineering Materials (Volume 967)
• Pages: 11-16
• DOI: https://doi.org/10.4028/p-Kfgx2c
• Online since: December 2023
• Authors: Kei Saito*, Tetsuya Hirade, Kenichi Takai
• Keywords: Ductility, Hydrogen Embrittlement, Lattice Defect, Martensitic Steel, Thermal Desorption Spectroscopy

References

[1] J.P. Hirth, Effects of hydrogen on the properties of iron and steel, Metall. Mater. Trans. A, 11 (1980) 861–890.

[2] M.L. Martin, M. Dadfarnia, A. Nagao, S. Wang, and P. Sofronis, Enumeration of the hydrogen-enhanced localized plasticity mechanism for hydrogen embrittlement in structural materials, Acta Mater. 165 (2019) 34–50.

DOI: 10.1016/j.actamat.2018.12.014

[3] M. Nagumo and K. Takai, The predominant role of strain-induced vacancies in hydrogen embrittlement of steels: Overview, Acta Mater. 165 (2019) 722–733.

DOI: 10.1016/j.actamat.2018.12.013

[4] M. Wang, E. Akiyama, and K. Tsuzaki, Hydrogen degradation of a boron-bearing steel with 1050 and 1300 MPa strength levels, Scr. Mater. 52 (2005) 403–408.

DOI: 10.1016/j.scriptamat.2004.10.023

[5] K. Saito, T. Hirade, and K. Takai, Hydrogen desorption spectra from excess vacancy-type defects enhanced by hydrogen in tempered martensitic steel showing quasi-cleavage fracture, Metall. Mater. Trans. A, 50 (2019) 5091–5102.

DOI: 10.1007/s11661-019-05450-3

[6] H. Saito, Y. Nagashima, T. Kuriharab, and T. Hyodo, A new positron lifetime spectrometer using a fast digital oscilloscope and BaF2 scintillators, Nucl. Instrum. Methods, 487 (2002) 612–617.

DOI: 10.1016/s0168-9002(01)02172-6

[7] P. Kirkegaard, J. V. Olsen, M. M. Eldrup, and N. J. Pedersen, PALS-fit, A computer program for analysing positron lifetime spectra, Denmark. Forskningscenter Risoe. Risoe-R, no. 1652(EN), Danmarks Tekniske Universitet, Risø Nationallabo ratoriet for Bæredygtig Energi, Roskilde, 2009.

[8] C. Hidalgo, G. Gonzalez-Doncel, S. Linderoth, and J. San Juan, Structure of dislocations in Al and Fe as studied by positron-annihilation spectroscopy, Phys. Rev. B, 13 (1992) 7017–7021.

DOI: 10.1103/physrevb.45.7017

[9] A. Vehanen, P. Hautojärvi, J. Johanson, J. Yli-Kauppila, and P. Moser,Vacancies and carbon impurities in α-iron: Electron irradiation, Phys. Rev. B, 25 (1982) 762–780.

DOI: 10.1103/physrevb.25.762