Evolution Behavior of Hydrogen-Induced Nano Voids in Al–Zn–Mg–Cu Aluminum Alloys under Loading

Gao, Haijun; Su, Hang; Shimizu, Kazuyuki; Kadokawa, Chihiro; Toda, Hiroyuki; Terada, Yasuko; Uesugi, Kentaro; Takeuchi, Akihisa

doi:10.2320/matertrans.m2018156

Cited by 7 publications

(5 citation statements)

References 21 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: 93%

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: 93%

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

et al. 2023

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“…where Eb is the trap binding energy ( the trap binding energy of each trap site is summarized in Table . 3 [24][25][26]43,44]), R is the gas constant (8.31 J mole -1 K -1 ), T is the absolute temperature, 𝜃 is the occupancy of the interstitial sites and 𝜃 is the occupancy of other trap sites. The total hydrogen concentration, 𝐶 , which represents the sum of the hydrogen stored in the normal interstitial lattice and all the trap sites is expressed as:…”

Section: Hydrogen Repartitioning Among Various Trap Sites During Defo...mentioning

confidence: 99%

Assessment of hydrogen embrittlement via image-based techniques in Al–Zn–Mg–Cu aluminum alloys

Toda

Shimizu

et al. 2019

Acta Materialia

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“…In addition, the growth behavior of nanovoids of Al-9.9Zn-2.3Mg-1.4Cu alloy has been analyzed using imaging-type tomography [57] . The nanovoids are uniformly distributed in the strain-localized region, and the accumulation and coalescence of nanovoids was not observed during deformation.…”

Section: D Crack Morphologymentioning

confidence: 99%

Local Deformation and Fracture Behavior of High-Strength Aluminum Alloys Under Hydrogen Influence

Shimizu

Toda

Uesugi

et al. 2019

Metall Mater Trans A

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The local deformation and fracture behavior of high-Zn Al-Zn-Mg(-Cu) alloys under hydrogen influence were investigated by in situ tests through synchrotron X-ray tomography. Intergranular and quasi-cleavage fractures were induced by hydrogen, and strain localization by the presence of cracks was not observed by 3D strain mapping. This result suggests that the strain localization at the crack tip is smaller than the measurement limit of 3D strain mapping. The average crack-tip-opening displacements, which are one of the crack driving forces specified by fracture mechanics, directly measured from the tomographic slice were 0.14 and 0.23 m for intergranular cracks and quasi-cleavage cracks, respectively. The crack driving force of the intergranular and quasi-cleavage cracks was small. The local deformation behavior at the crack tips was analyzed based on fracture mechanics. The local deformation field of the crack tip, which was characterized using the Rice-Drugan-Sham (RDS) solution rather than the Hutchinson-Rice-Rosengren (HRR) solution, was located within 20 m of the crack tip, and its size was limited. The results of this work clarify that the intergranular and quasi-cleavage crack growth are caused by small driving forces; however, this behavior is not perfectly brittle, accompanying local deformation at the crack tip.

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Evolution Behavior of Hydrogen-Induced Nano Voids in Al–Zn–Mg–Cu Aluminum Alloys under Loading

Cited by 7 publications

References 21 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

Assessment of hydrogen embrittlement via image-based techniques in Al–Zn–Mg–Cu aluminum alloys

Local Deformation and Fracture Behavior of High-Strength Aluminum Alloys Under Hydrogen Influence

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