Grain structure and quench-rate effects on strength and toughness of AA7050 Al-Zn-Mg-Cu-Zr alloy plate

Dorward, R. C.; Beerntsen, D. J.

doi:10.1007/bf02671263

Cited by 81 publications

(33 citation statements)

References 11 publications

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“…As a result, partial recrystallization with plenty of sub-grains in the unrecrystallized zone is obtained after solution heat treatment. Recrystallization increases the amount of random high angle grain boundaries and often makes coherent Al 3 Zr dispersoids lose coherency with the matrix [14] . Consequently, a lot of equilibrium particles precipitate preferentially on these incoherent dispersoids with increase in transfer time, which results in loss of solutes in the matrix and less volume fraction of hardening precipitates after aging.…”

Section: Discussionmentioning

confidence: 99%

Influence of quench transfer time on microstructure and mechanical properties of 7055 aluminum alloy

You

Liu

Zhang

et al. 2008

J. Cent. South Univ. Technol.

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The influence of quench transfer time on the microstructure and mechanical properties of 7055 aluminum alloy with and without zirconium was investigated by tensile properties test, optical microscopy, scanning electron microscopy and transmission electron microscopy. For the Zr-free alloy, the strength increases to the highest value at 20 s with transfer time, and then decreases slightly. The elongation decreases slowly with transfer time within 20 s, and more rapidly after 20 s. For the Zr-containing alloy, prolonging transfer time within 20 s results in slight decrease in the strength and elongation, and rapid drop of which is observed after 20 s. For the Zr-free alloy, prolonging transfer time can increase the percentage of intergranular fracture, which is mainly caused by wide grain boundary precipitate free zone. The failure mode of the Zr-containing alloy is modified from the predominant transgranular void growth and intergranular fracture to transgranular shear and intergranular fracture with increase in the transfer time, which is attributed to the wider grain boundary precipitate free zone and coarse equilibrium phases in the matrix.

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Section: Discussionmentioning

confidence: 99%

Influence of quench transfer time on microstructure and mechanical properties of 7055 aluminum alloy

You

Liu

Zhang

et al. 2008

J. Cent. South Univ. Technol.

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“…Thus, it is thought that the spray deposition technique could be used to enhance the mechanical properties of aluminum alloys. The additions of Mg and Zn enhanced the mechanical properties because of the η'-MgZn 2 precipitates after the aging treatment [17,18]. The addition of other alloying elements were also effective to enhance the properties.…”

Section: Introductionmentioning

confidence: 99%

Hot Deformation Behavior of a Spray-Deposited Al-8.31Zn-2.07Mg-2.46Cu-0.12Zr Alloy

Sheng

Lei

Xiao

et al. 2017

Metals

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Abstract:Metallic materials have a significant number of applications, among which Al alloys have drawn people's attention due to their low density and high strength. High-strength Al-based alloys, such as 7XXX Al alloys, contain many alloying elements and with high concentration, whose microstructures present casting voids, segregation, dendrites, etc. In this work, a spray deposition method was employed to fabricate an Al-8.31Zn-2.07Mg-2.46Cu-0.12Zr (wt %) alloy with fine structure. The hot deformation behavior of the studied alloy was investigated using a Gleeble 1500 thermal simulator and electron microscopes. The microstructure evolution, variation in the properties, and precipitation behavior were systematically investigated to explore a short process producing an alloy with high property values. The results revealed that the MgZn 2 particles were detected from inside the grain and grain boundary, while some Al 3 Zr particles were inside the grain. An Arrhenius equation was employed to describe the relationship between the flow stress and the strain rate, and the established constitutive equation was that: Figure 7 gives the hardness variations of the hot compressed samples aged at 120 • C fo durations. For the samples after being hot-compressed at strain rates of 1 s −1 and 0.001 s −1 , present the same trend. The initial hardness of compressed samples increased with the hot de temperature. The hardness of the hot-compressed samples increased with the aging time, a kept constant as they were aging at certain temperatures for 15 h.Metals 2017, 7, 299 deformation temperature. The hardness of the hot-compressed samples increased with the and almost kept constant as they were aging at certain temperatures for 15 h. Discussion Constitutive EquationThe constitutive relationships were used to describe the hot deformation behavior. Som are employed to reveal the hot deformation behavior, in which one of the most extended v the hot working constitutive equation is as follows [24]:where ε is the strain rate; A is a material constant which is independent of temperature true stress; Q is the activation energy; R is the gas constant (8.31); and T is the absolute tem (K). At low stress lever (ασ < 0.8):At high stress lever (ασ > 1.2):(σ) σ n F  , β and n are the material constants, α = β/n. Substituting Equations (2) and (3) (4) and (5), respectively, gives:The values of n and β are from the slopes of the lines in ln ε and σ, lnε and ln σ , Discussion Constitutive EquationThe constitutive relationships were used to describe the hot deformation behavior. Som are employed to reveal the hot deformation behavior, in which one of the most extended v the hot working constitutive equation is as follows [24]:where .ε is the strain rate; A is a material constant which is independent of temperature; σ is stress; Q is the activation energy; R is the gas constant (8.31); and T is the absolute tempera At low stress lever (ασ < 0.8):At high stress lever (ασ > 1.2): F(σ) = σ n , β and n are the material constants, α = β/n. Substit...

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“…As shown in the Table 1, the recrystallised area fraction of Zr-containing alloys is less than that of Cr-containing alloys, being attributable to Zr reducing recrystallisation more effectively than Cr. As recrystallisation has direct influence on yield strength and toughness of 7xxx alloys, by decreasing yield strength and toughness with increasing recrystallisation fraction [23], it is, hence, a major concern for selection of materials for aerospace applications.…”

Section: Discussionmentioning

confidence: 99%

Identification and analysis of intermetallic phases in overaged Zr-containing and Cr-containing Al–Zn–Mg–Cu alloys

Starink

2011

Journal of Alloys and Compounds

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This paper investigates the effect of alloying elements on the characteristics of intermetallic phases in Zr-containing and Cr-containing 7xxx Al-Zn-Mg-Cu alloys at overaged conditions. Four Al-Zn-Mg-Cu alloy plates with different alloying element contents were studied by optical microscopy based image analysis, differential scanning calorimetry, scanning electron microscopy combined with energy disperse X-ray spectroscopy and transmission electron microscopy. The grain structures, recrystallisation, intermetallic phases and precipitates in the selected alloys have been analysed and the presence of coarse intermetallic phases has been interpreted using established phase diagrams. The different effects of Zr or Cr addition to the alloys have been compared. The experimental results showed that the recrystallised area fraction of Zr-containing alloys is less than that of Cr-containing alloys, being attributable to Zr reducing recrystallisation more effectively than Cr. The detected particles are mainly S phase, Al7Cu2Fe, as well as dispersoids of Al3Zr for Zr-containing alloys and Cr-rich E phase for Cr-containing alloys. These coarse particles, especially the S phase which can not be dissolved during solution treatment, are detrimental to the fracture toughness of the alloys.

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Grain structure and quench-rate effects on strength and toughness of AA7050 Al-Zn-Mg-Cu-Zr alloy plate

Cited by 81 publications

References 11 publications

Influence of quench transfer time on microstructure and mechanical properties of 7055 aluminum alloy

Influence of quench transfer time on microstructure and mechanical properties of 7055 aluminum alloy

Hot Deformation Behavior of a Spray-Deposited Al-8.31Zn-2.07Mg-2.46Cu-0.12Zr Alloy

Identification and analysis of intermetallic phases in overaged Zr-containing and Cr-containing Al–Zn–Mg–Cu alloys

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