Effect of Copper Addition on Precipitation Behavior near Grain Boundary in Al–Zn–Mg Alloy

Matsuda, Kenji; Yasumoto, Toru; Bendo, Artenis; Tsuchiya, Taiki; Lee, Seungwon; Nishimura, K.; Nunomura, Norio; Marioara, Calin Daniel; Levik, Adrian; Holmestad, Randi; Toda, Hiroyuki; Yamaguchi, Masatake; Ikeda, Ken; Homma, Tomoyuki; Ikeno, Susumu

doi:10.2320/matertrans.l-m2019828

Cited by 25 publications

(4 citation statements)

References 23 publications

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“…These concentrated Cu atoms replaced Ag atoms because the Ag concentration was lower in the corresponding area, while Au was relatively homogeneously distributed over the entire particle, except at the Au–Cu ordered positions. The formation of these types of clusters and precipitates at the defects and boundaries has been reported for a variety of alloy systems. − …”

Section: Resultsmentioning

confidence: 99%

Atomically Localized Ordered Phase and Segregation at Grain Boundaries in Au–Ag–Cu Ternary Alloy Nanoparticles

Yasuhara

Sannomiya

2022

J. Phys. Chem. C

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Metallic nanoparticles have been widely used and investigated because of their unique electrical and optical properties as well as their catalytic functions. The degree of freedom for tuning the material properties, such as electrical conductivity, permittivity, and mechanical strength, is significantly extended by alloying multiple metal elements, for example, in high-entropy alloys. For catalysis applications, the interfaces between the different phases and grain boundaries in the nanoparticles play an important role because the catalytic reactions occur most efficiently at the interfaces. The interfaces are also crucial for the chemical stability of the alloy. In the present work, we synthesized Au–Ag–Cu ternary alloy nanoparticles and investigated their atomically localized structures, particularly at the grain boundaries. To investigate the interface structure in the nanoparticles, we used scanning transmission electron microscopy with a spherical aberration corrector and energy dispersive X-ray spectroscopy. In the solid solution particles, L10 ordered phases with sizes of a few lattice sites, around 2 nm in diameter, were found at the defect sites between the twin boundaries. In the phase-separated alloy particles, segregated Ag atoms, which are not soluble in the Cu-rich phase, were found specifically at the grain boundaries with finite thicknesses.

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Section: Resultsmentioning

confidence: 99%

Atomically Localized Ordered Phase and Segregation at Grain Boundaries in Au–Ag–Cu Ternary Alloy Nanoparticles

Yasuhara

Sannomiya

2022

J. Phys. Chem. C

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“…In Al–Zn–Mg–Cu alloys, the PFZ can be divided into a PFZ near the grain boundary (n‐PFZ) and a conventional PFZ (con‐PFZ) with a wider width. [ 27 ] While the n‐PFZ does not contain any precipitates, in the con‐PFZ clusters containing only Al, Cu, and Mg (GPB‐II zones) are formed at the beginning of aging. These GPB‐II zones will not transform into S′ phases, but dissolve at over aged state.…”

Section: Resultsmentioning

confidence: 99%

Effect of retrogression re‐aging treatment on the stress corrosion behavior of the 7075 Al–Zn–Mg–Cu alloy

Liu

Guo

et al. 2022

Materials & Corrosion

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This paper studies the influence of the regression re-aging (RRA) process on the mechanical properties and corrosion resistance of 7075. In the RRA heat treatment, the material properties are markedly affected by the variation of parameters in the regression stage. When the regression temperature and the regression duration increase, the mechanical properties of the material decrease. There was no intergranular corrosion in the samples treated by RRA, while obvious intergranular corrosion occurred in the T6 sample. Compared with the T6 sample, the RRA-190-0.5 sample with optimized parameters has a higher density of the precipitated phase and narrower precipitate-free zone, and the precipitated phase along the grain boundary is discontinuous, isolated, and short. Compared with the single-stage peak aging treatment, the RRA treatment can considerably improve the corrosion resistance and stress corrosion resistance but slightly reduce the strength. The best heat treatment process condition is 120°C/24 h + 190°C/0.5 h + 120°C/24 h.

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“…During the aging process, a high density of solute-rich nano-sized particles precipitate, thereby strengthening the alloys. The precipitation kinetics and strengthening behavior of hardening phases in Al-Zn-Mg alloys have been the subject of considerable attention in recent decades, with a substantial body of research published in this area [3][4][5][6][7][8][9]. Another strengthening approach, which involves a reduction in grain size, has been extensively researched over the past few decades in accordance with the classical Hall-Petch relationship [10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Precipitation Thermodynamics in an Al–Zn–Mg Alloy with Different Grain Sizes

Wang,

Huang,

Zhang

et al. 2024

Metals

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In order to gain insight into the influence of grain size on precipitation thermodynamics, bulk materials of coarse-grained (CG), ultrafine-grained (UFG) (with or without dislocations), and nanocrystalline (NC) 7075 Al alloy have been fabricated by solid solution treatment, equal-channel angular pressing (ECAP), or high-pressure torsion (HPT) processes. The precipitation behavior and the corresponding thermal phenomenon were studied by transmission electron microscopy (TEM) and differential scanning calorimetry (DSC) heating. The results indicated that there are significant differences in precipitation thermodynamics among the four bulk materials. In the CG and UFG materials without dislocations, homogeneous nucleation is the primary precipitation mechanism. However, the nucleation of the GP zones is suppressed at lower temperatures due to a reduction in the number of residual vacancies and the supersaturation in the UFG interiors. This is attributed to the absorption of vacancies and solute atoms by a greater volume of grain boundaries. It can be observed that the greater the excess of vacancies remaining in grain interiors, the lower the temperature at which nucleation of GP zones occurs. Defect-assisted heterogeneous nucleation was identified as the predominant precipitation mechanism in the UFG materials with dislocations and the NC materials. These defects encompass dislocations, lattice distortions, and grain boundaries. The decomposition processes of solid solutions were found to be almost complete at a lower temperature. The presence of dislocations, lattice distortions, and grain boundaries enables solute atoms to diffuse at a much faster rate, significantly enhancing the precipitation rate and reducing the nucleation and formation energies of various precipitate phases.

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Effect of Copper Addition on Precipitation Behavior near Grain Boundary in Al–Zn–Mg Alloy

Cited by 25 publications

References 23 publications

Atomically Localized Ordered Phase and Segregation at Grain Boundaries in Au–Ag–Cu Ternary Alloy Nanoparticles

Atomically Localized Ordered Phase and Segregation at Grain Boundaries in Au–Ag–Cu Ternary Alloy Nanoparticles

Effect of retrogression re‐aging treatment on the stress corrosion behavior of the 7075 Al–Zn–Mg–Cu alloy

Precipitation Thermodynamics in an Al–Zn–Mg Alloy with Different Grain Sizes

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