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Cabrini M, Coppola L, Lorenzi S, Testa C, Carugo F, Bucella DP, Pastore T. Hydrogen Permeation in X65 Steel under Cyclic Loading. Materials (Basel) 2020; 13:ma13102309. [PMID: 32429576 PMCID: PMC7287996 DOI: 10.3390/ma13102309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 05/03/2020] [Accepted: 05/13/2020] [Indexed: 06/11/2023]
Abstract
This experimental work analyzes the hydrogen embrittlement mechanism in quenched and tempered low-alloyed steels. Experimental tests were performed to study hydrogen diffusion under applied cyclic loading. The permeation curves were fitted by considering literature models in order to evaluate the role of trapping-both reversible and irreversible-on the diffusion mechanism. Under loading conditions, a marked shift to the right of the permeation curves was noticed mainly at values exceeding the tensile yield stress. In the presence of a relevant plastic strain, the curve changes due to the presence of irreversible traps, which efficiently subtract diffusible atomic hydrogen. A significant reduction in the apparent diffusion coefficient and a considerable increase in the number of traps were noticed as the maximum load exceeded the yield strength. Cyclic loading at a tensile stress slightly higher than the yield strength of the material increases the hydrogen entrapment phenomena. The tensile stress causes a marked and instant reduction in the concentration of mobile hydrogen within the metal lattice from 55% of the yield strength, and it increases significantly in the plastic field.
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Affiliation(s)
- Marina Cabrini
- Department of Engineering and Applied Sciences, University of Bergamo, 24129 Bergamo, Italy; (M.C.); (L.C.); (C.T.); (F.C.); (D.P.B.); (T.P.)
- CSGI Consortium, Unity of Bergamo, 24129 Bergamo, Italy
| | - Luigi Coppola
- Department of Engineering and Applied Sciences, University of Bergamo, 24129 Bergamo, Italy; (M.C.); (L.C.); (C.T.); (F.C.); (D.P.B.); (T.P.)
- CSGI Consortium, Unity of Bergamo, 24129 Bergamo, Italy
- INSTM Consortium, Unity of Bergamo, 24129 Bergamo, Italy
| | - Sergio Lorenzi
- Department of Engineering and Applied Sciences, University of Bergamo, 24129 Bergamo, Italy; (M.C.); (L.C.); (C.T.); (F.C.); (D.P.B.); (T.P.)
- CSGI Consortium, Unity of Bergamo, 24129 Bergamo, Italy
- INSTM Consortium, Unity of Bergamo, 24129 Bergamo, Italy
| | - Cristian Testa
- Department of Engineering and Applied Sciences, University of Bergamo, 24129 Bergamo, Italy; (M.C.); (L.C.); (C.T.); (F.C.); (D.P.B.); (T.P.)
- CSGI Consortium, Unity of Bergamo, 24129 Bergamo, Italy
- INSTM Consortium, Unity of Bergamo, 24129 Bergamo, Italy
| | - Francesco Carugo
- Department of Engineering and Applied Sciences, University of Bergamo, 24129 Bergamo, Italy; (M.C.); (L.C.); (C.T.); (F.C.); (D.P.B.); (T.P.)
- CSGI Consortium, Unity of Bergamo, 24129 Bergamo, Italy
- INSTM Consortium, Unity of Bergamo, 24129 Bergamo, Italy
| | - Diego Pesenti Bucella
- Department of Engineering and Applied Sciences, University of Bergamo, 24129 Bergamo, Italy; (M.C.); (L.C.); (C.T.); (F.C.); (D.P.B.); (T.P.)
- CSGI Consortium, Unity of Bergamo, 24129 Bergamo, Italy
- INSTM Consortium, Unity of Bergamo, 24129 Bergamo, Italy
| | - Tommaso Pastore
- Department of Engineering and Applied Sciences, University of Bergamo, 24129 Bergamo, Italy; (M.C.); (L.C.); (C.T.); (F.C.); (D.P.B.); (T.P.)
- INSTM Consortium, Unity of Bergamo, 24129 Bergamo, Italy
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