Influence of nanovoids in the hydrogen embrittlement fracture of Al–Zn–Mg–Cu alloys

Shimizu, Kazuyuki; Toda, Hiroyuki; Kadogawa, Chihiro; Fujihara, Hiro; Takeuchi, Akihisa

doi:10.1016/j.mtla.2020.100667

Cited by 14 publications

(6 citation statements)

References 45 publications

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“…Furthermore, the growth or merging of nanovoids caused by hydrogen is not seen even before fracture, suggesting that nanovoids do not play a dominant role in inducing quasicleavage cracks in Al-Zn-Mg-Cu aluminum alloys 2 . In addition, neither growth nor coalescence of hydrogen-induced nanovoids are observed even just before fracture, indicating that nanovoids do not behave as the dominant factor of hydrogen-induced quasicleavage cracks in Al-Zn-Mg-Cu aluminum alloys 64,65 . For grain boundaries, it has been reported that if large amounts of hydrogen are enriched at the aluminum grain boundary, hydrogen-induced debonding can occur, analogous to the precipitate interface 29 .…”

Section: 𝜃 T 𝑖 1 − 𝜃 Tmentioning

confidence: 94%

“…Holding time is a parameter that can be considered equivalent to the strain rate in slow strain rate tensile testing, and the effect of increased holding time is interpreted as a decrease in the strain rate. Hydrogen repartitioning or hydrogen invasion from outside the specimen occurs during the tensile deformation process [65][66][67] , making hydrogen embrittlement more pronounced at longer holding times (lower strain rates). This phenomenon occurs due to the complicated superposition of the formation of local stress gradients, changes in hydrogen trap site density due to loading, hydrogen diffusion during deformation, and hydrogen invasion caused by the fracture of the passive film on the aluminum surface.…”

Section: 𝜃 T 𝑖 1 − 𝜃 Tmentioning

confidence: 99%

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Hydrogen Embrittlement and its Prevention in 7XXX Aluminum Alloys with High Zn Concentrations

et al. 2023

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7xxx aluminum alloys are representative high-strength aluminum alloys; however, mechanical property degradation due to hydrogen hinders further strengthening. We have previously reported that hydrogen embrittlement in 7xxx alloys originates from trapped hydrogen at the MgZn2 precipitate interface, providing high hydrogen trapping energy. We propose the dispersion of Mn-based second-phase particles as a novel technique for preventing 7xxx aluminum alloy hydrogen embrittlement. In this study, the deformation and fracture behaviors of high hydrogen 7xxx alloys containing 0.0% Mn and 0.6% Mn are observed in situ using synchrotron radiation X-ray tomography. Although no significant differences appear between the two alloys regarding the initiation of quasicleavage cracks, the area fractions of final quasicleavage fractures are 16.5% and 1.0% for 0.0%Mn and 0.6%Mn alloys, respectively; this finding indicates that the Mn addition reduces hydrogen-induced fractures. The obtained macroscopic hydrogen embrittlement is quantitatively analyzed based on hydrogen partitioning in alloys. Adding 0.6% Mn, generating second-phase particles with high hydrogen trapping abilities, significantly suppresses hydrogen-induced quasicleavage fracture. The results of an original hydrogen partitioning analysis show that the dispersion of Mn-based particles (Al12Mn3Si) with high hydrogen trapping abilities reduces the hydrogen concentration at the semicoherent MgZn2 interface and suppresses hydrogen embrittlement.

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Section: 𝜃 T 𝑖 1 − 𝜃 Tmentioning

confidence: 94%

Section: 𝜃 T 𝑖 1 − 𝜃 Tmentioning

confidence: 99%

Hydrogen Embrittlement and its Prevention in 7XXX Aluminum Alloys with High Zn Concentrations

et al. 2023

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“…Details of the quantification of the trap site densities are available elsewhere. 13,16,21,41) The number of hydrogen atoms that a trap site can trap per unit number, unit length, unit area, and unit volume (herein called the hydrogen trap interval) has been reported using first-principles calculations. 13,19,3036) The reported hydrogen trap intervals are 1.0 atomH/atom for the solute Mg atoms, 32) 1.0 atomH/nm for the edge dislocation, 31) 1.2 atomH/nm for the screw dislocation, 31) 8 atomH/vacancy for the vacancy, 34) 21.9 atomH/nm 2 for the grain boundary, 33) 17.1 atomH/nm 2 for the coherent interface of the MgZn 2 precipitate, 13,35) 5.6 atomH/nm 2 for the semi-coherent interface the MgZn 2 precipitate, 36) 13.2 atomH/nm 3 for the Al 7 Cu 2 Fe particle, 19) and also 20 atomH/nm 2 for the micropore.…”

Section: Hydrogen Partitioning Behaviormentioning

confidence: 99%

Suppression of Hydrogen Embrittlement due to Local Partitioning of Hydrogen to Dispersed Intermetallic Compound Particles in Al–Zn–Mg–Cu Alloys

et al. 2022

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Recent studies have revealed that hydrogen embrittlement in AlZnMg alloys appears to be dominated by hydrogen partitioning to MgZn 2 precipitates. A method has recently been proposed for reducing the hydrogen concentration at MgZn 2 precipitates by adding specific intermetallic compound particles that have high hydrogen trap energy. In the present study, the effectiveness of Al 7 Cu 2 Fe particles on suppression of hydrogen embrittlement in AlZnMgCu alloys was evaluated using X-ray microtomography. Quasi-cleavage cracks were found to be initiated in regions where local volume fractions of the Al 7 Cu 2 Fe particles were relatively low. Hydrogen partitioning to the MgZn 2 precipitate interface was suppressed, even in high hydrogen concentration material, by adding Al 7 Cu 2 Fe particles. However, the fractional area of the quasi-cleavage fracture in the material with high hydrogen concentration was higher due to insufficient hydrogen diffusion inside the Al 7 Cu 2 Fe particles and at the interface between the aluminum matrix and the particles. It appears that finely distributed small Al 7 Cu 2 Fe particles might effectively suppress hydrogen embrittlement.

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“…In the localized deformation region, it was reported that the number of vacancies increased approximately 10 4 times while that of dislocations increased approximately several times due to deformation. 6,22) In addition, the hydrogen binding energy of dislocation is 16.4 kJ/mol, and this value is relatively low for the trapping sites in aluminum. 23) Since the binding energy of vacancies is 28 kJ/mol and higher than the value for dislocation, the accumulated hydrogen is preferentially repartitioned to vacancy.…”

Section: Effect Of the Mechanical And Microstructural Factors On Hydrogen Accumulationmentioning

confidence: 99%

Assessment of Hydrogen Accumulation Behavior in Al–Zn–Mg Alloy under Strain with Kelvin Force Microscopy

et al. 2021

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Hydrogen embrittlement in aluminum alloys occurs due to local hydrogen accumulation during deformation. Investigating hydrogen diffusion with plastic deformation can help researchers further understand hydrogen embrittlement behavior in terms of its occurrence condition. We assessed hydrogen accumulation behavior in AlZnMg alloys under strain by combining tensile testing with Kelvin force microscopy. Additionally, the effects of microstructures on hydrogen accumulation were analyzed in detail. Hydrogen accumulated around specific grain boundaries, and it was likely that accumulated hydrogen was repartitioned to the generated vacancies, due to deformation, and the precipitate interfaces.

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Influence of nanovoids in the hydrogen embrittlement fracture of Al–Zn–Mg–Cu alloys

Cited by 14 publications

References 45 publications

Hydrogen Embrittlement and its Prevention in 7XXX Aluminum Alloys with High Zn Concentrations

Hydrogen Embrittlement and its Prevention in 7XXX Aluminum Alloys with High Zn Concentrations

Suppression of Hydrogen Embrittlement due to Local Partitioning of Hydrogen to Dispersed Intermetallic Compound Particles in Al–Zn–Mg–Cu Alloys

Assessment of Hydrogen Accumulation Behavior in Al–Zn–Mg Alloy under Strain with Kelvin Force Microscopy

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