Effect of Zr content on quench sensitivity of AIZnMgCu alloys

Liu, Shengdan; Zhang, Xinming; Chen, Ming-an; You, Jiang-hai; Zhang, Xiaoyan

doi:10.1016/s1003-6326(07)60175-7

Cited by 37 publications

(7 citation statements)

References 13 publications

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“…Liu et al (2007) found that a low chromium content in 7000-series alloys promotes lower quench sensitivity. Based on the finding of Liu et al (2007), the chromium present in AA7075 results in large incoherent dispersoids which act as nucleation sites for heterogenous precipitation. During a rapid quench, there is not enough time for precipitates to form around the dispersoids and thus the material will have a high level of supersaturation, which will promote greater age hardening.…”

Section: Resultsmentioning

confidence: 99%

“…In general, it has been well established that both Cr and Zr affect recrsytallization, as well as quench sensitivity (Conserva et al, 1971). Liu et al (2007) found that a low chromium content in 7000-series alloys promotes lower quench sensitivity. Based on the finding of Liu et al (2007), the chromium present in AA7075 results in large incoherent dispersoids which act as nucleation sites for heterogenous precipitation.…”

Section: Resultsmentioning

confidence: 99%

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Process parameters for hot stamping of AA7075 and D-7xxx to achieve high performance aged products

Omer

Abolhasani

Kim

et al. 2018

Journal of Materials Processing Technology

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This work examines the necessary process parameters for die quenching (DQ) during hot stamping and subsequent age hardening and paint bake cycle (PBC) response for two alloys: AA7075 and a developmental 7xxx alloy (referred to as AA7xxx), with a lower Chromium content, higher Zirconium content and higher Zinc-to-Magnesium ratio in comparison to AA7075. For both alloys, a minimum solutionizing time of 8 minutes was found to be required, along with a minimum quench rate of 56°C/s and 27°C/s for AA7075 and AA7xxx, respectively. Two-step aging treatments, leveraging a paint bake cycle (PBC) of 177°C for 30 minutes as the second step, were considered after die quenching and were devised to achieve T6-or T76-level strengths. For AA7075, an aging treatment of 120°C for 8 hours, followed by the paint bake cycle (PBC) produced strength levels similar to a T6 temper. DSC experiments showed that the microstructure from this heat treatment was similar to a peak-aged T6 temper. For AA7xxx, a treatment of 100°C for 4 hours and followed by the paint bake produced a strength similar to a T76 temper, while 120°C for 3 hours followed by the paint bake yielded T6 strength levels. The properties of the custom aging treatments were validated through tensile tests. The resulting stress-strain curves show that it is possible to achieve T6 or T76 properties using a custom aging treatment incorporating the PBC that is 65-83% shorter than standard T6 or T76 treatments.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Process parameters for hot stamping of AA7075 and D-7xxx to achieve high performance aged products

Omer

Abolhasani

Kim

et al. 2018

Journal of Materials Processing Technology

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“…Large-scale Al-Zn-Mg-Cu-Zr ingots with fine structure have been successfully fabricated by the spray deposition technology in our previous work [ 25 , 26 ]. The obtained ingots contain fine grains due to the rapid solidification and alloying [ 27 , 28 , 29 ]. Most investigations focus on the microstructure and properties of the spray-deposited Al-Zn-Mg-Cu alloy in the lab scale [ 26 , 30 ].…”

Section: Introductionmentioning

confidence: 99%

Precipitation Behavior and Quenching Sensitivity of a Spray Deposited Al-Zn-Mg-Cu-Zr Alloy

et al. 2017

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Precipitation behavior and the quenching sensitivity of a spray deposited Al-Zn-Mg-Cu-Zr alloy during isothermal heat treatment have been studied systematically. Results demonstrate that both the hardness and the ultimate tensile strength of the studied alloy decreased with the isothermal treatment time at certain temperatures. More notably, the hardness decreases rapidly after the isothermal heat treatment. During isothermal heat treatment processing, precipitates readily nucleated in the medium-temperature zone (250-400 • C), while the precipitation nucleation was scarce in the low-temperature zone (<250 • C) and in the high-temperature zone (>400 • C). Precipitates with sizes of less than ten nanometers would contribute a significant increase in yield strength, while the ones with a larger size than 300 nm would contribute little strengthening effect. Quenching sensitivity is high in the medium-temperature zone (250-400 • C), and corresponding time-temperature-property (TTP) curves of the studied alloy have been established.

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“…However, magnesium alloys exhibit low workability due to the limited number of slip systems associated with hexagonal close packaged (HCP) crystal structure. Currently, most of magnesium alloy components are used in the as-cast condition, which are hard to meet high performance service requirements [2]. Compared to the castings, magnesium alloys subject to plastic deformation exhibit improved strength and ductility, loading bearing capacity, shock resistance ability, etc.…”

Section: Introductionmentioning

confidence: 99%

Process design based on FE simulations and experiments of forging a complex-shaped magnesium alloy adaptor

et al. 2017

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-High-strength magnesium alloys show great potentials for aviation and aerospace applications due to their special strength and low density, but these are difficult to form because of the poor formability and narrow, feasible forging-temperature ranges. Isothermal forging is an effective method to manufacture complex-shaped components with a magnesium alloy, in which the avoidance of forming defects and improvement of mechanical properties are of great concern. The process design of complex-shaped MB26 magnesium alloy adaptor based on finite element (FE) simulations and forging experiments was conducted in this study. A combined female-die was used in order to remove the adaptor forging with three branches. Different forming schemes were analyzed and compared through finite element method (FEM) simulations and forging experiments. The results showed that, compared with a one-step forging process, two-steps forging was more appropriate for forming the adaptor, which not only improved the filling quality but also reduced the forging load. In addition, the aging treatment after hot forging could only slightly improve the mechanical properties of the MB26 adaptor forging, because of the minor addition of rare earth (RE) elements.

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Effect of Zr content on quench sensitivity of AIZnMgCu alloys

Cited by 37 publications

References 13 publications

Process parameters for hot stamping of AA7075 and D-7xxx to achieve high performance aged products

Process parameters for hot stamping of AA7075 and D-7xxx to achieve high performance aged products

Precipitation Behavior and Quenching Sensitivity of a Spray Deposited Al-Zn-Mg-Cu-Zr Alloy

Process design based on FE simulations and experiments of forging a complex-shaped magnesium alloy adaptor

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