Aging behavior and precipitate characterization of a high Zn-containing Al-Zn-Mg-Cu alloy with various tempers

Wen, Kai; Fan, Yunqiang; Wang, Guojun; Jin, Longbin; Li, Xiwu; Li, Zhihui; Zhang, Yongan; Xiong, Baiqing

doi:10.1016/j.matdes.2016.03.150

Cited by 133 publications

(31 citation statements)

References 21 publications

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“…For AlZnMg alloys, the typical precipitate sequence is a fi GP fi g¢-MgZn 2 fi g-MgZn 2 . [12,14,27,35] Based on the brightfield TEM images shown in Figure 13, high-density short rod-shaped fine precipitates ranging in the size from 5 to 10 nm are observed in the microstructure, which has been confirmed to be the g¢-MgZn 2 phase. [27] C. Mechanical Properties of the Al-Mg-Si-Zn Alloys…”

Section: Resultsmentioning

confidence: 99%

“…Table IV summarizes the precipitates observed in Al-Mg-Znbased alloys. [12][13][14]27,31,32,34,35] g-Type precipitates are observed in alloys with magnesium concentration below 2.5 wt pct, while s-Mg 32 (Al, Zn) 49 phases are observed for relatively high magnesium concentration. A numerical model has also been established to prove that the s phase exists with the increasing Mg content in Al-6 wt pct Zn-2 wt pct Cu-(1 to 4) wt pct Mg alloys.…”

Section: Resultsmentioning

confidence: 99%

“…[12,14,16,20] The strength of the T6 temper is significantly affected by the zinc concentration. Both the yield strength and UTS decrease with the decreasing zinc content.…”

Section: Resultsmentioning

confidence: 99%

“…Owing to fine-scale precipitation of metastable Zn-and Mg-rich phases, the strength of Al-Zn-Mg-Cu alloys can reach a level of 650 MPa for the yield strength and 700 MPa for the UTS after aging at 120°C for 24 hours. [12] Yang et al [13] investigated an Al-Zn-Mg alloy with a Mg-to-Zn atomic ratio of 0.34 to improve the strength through formation of the coherent polyhedral s-phase [(Al, Zn) 49 Mg 32 ]. Li et al [14] investigated solution treatment of the microalloyed Al-Zn-Mg alloy system with Sc and Zr and found that both g¢-MgZn 2 precipitates and fine Al 3 (Sc, Zr) particles are homogenously distributed throughout the a-Al grains under heat-treatment conditions.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Zn Concentration on the Microstructure and Mechanical Properties of Al-Mg-Si-Zn Alloys Processed by Gravity Die Casting

Zhu

et al. 2018

Metall Mater Trans A

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The microstructure and mechanical properties of Al-8.1Mg-2.6Si-(0.08 to 4.62)Zn alloys (in wt pct) have been investigated by the permanent mold casting process. X-ray diffraction analysis shows that the s-Mg 32 (Al, Zn) 49 phase forms when the Zn content is 1.01 wt pct. With higher Zn contents of 2.37 and 3.59 wt pct, the g-MgZn 2 and s-Mg 32 (Al, Zn) 49 phases precipitate in the microstructure, and the g-MgZn 2 phase forms when the Zn content is 4.62 wt pct. Metallurgical analysis shows that the g-MgZn 2 and s-Mg 32 (Al, Zn) 49 phases strengthen the Al-8.1Mg-2.6Si-(0.08 to 4.62)Zn alloys. After solutionizing at 510°C for 180 minutes and aging at 180°C for 90 minutes, the g¢-MgZn 2 phase precipitates in the a-Al matrix, which significantly enhances the mechanical properties. Addition of 3.59 wt pct Zn to the Al-8.1Mg-2.6Si alloy with heat treatment increases the yield strength from 96 to 280 MPa, increases the ultimate tensile strength from 267 to 310 MPa, and decreases the elongation from 9.97 to 1.74 pct.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…[12,14,16,20] The strength of the T6 temper is significantly affected by the zinc concentration. Both the yield strength and UTS decrease with the decreasing zinc content.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of Zn Concentration on the Microstructure and Mechanical Properties of Al-Mg-Si-Zn Alloys Processed by Gravity Die Casting

Zhu

et al. 2018

Metall Mater Trans A

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“…Due to attractive combinations of (relatively) high strength and low density, 7000 series aluminium alloys (such as the 7175-T7351 alloy considered in the present work) have numerous naval, aerospace, and military applications [4][5][6] and have consequently received a great deal of attention in the literature. In the work of Benoit et al, for example, the microstructure of two 7000 series alloys was analysed, in addition to fundamental mechanical response parameters such as yield stress, ultimate tensile strength, elongation at fracture, and fracture initiation energy [4].…”

Section: Introductionmentioning

confidence: 99%

Investigations into Taylor-Quinney coefficient determination for a 7000 series aluminium alloy using a novel small specimen test technique

Rouse

Hyde

Kazakeviciute

2018

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Thermo-mechanical coupling is a critical component in the thermodynamics of irreversible processes and is related to the dissipation of thermal energy during plastic straining. The Taylor-Quinney coefficient may be thought of as a ratio between thermally dissipated energy and plastic work, thereby giving insight into the thermomechanical coupling term. The inclusion of this parameter in a meaningful way is complicated by the various dependencies that the Taylor-Quinney coefficient may be subject to (e.g. loading rate and temperature). Determination of these dependencies is usually achieved through extensive experimentation, wherein temperature variations are monitored (with reference to an unloaded control sample) in a test piece during mechanical loading. There are practical limitations in full size testing methods however, not least relating to the location of full sized control and loaded samples in an environment chamber/furnace while simultaneously maintaining (control sample) temperature uniformity and high resolution temperature measurement (in the loaded sample). The present work details a method based on a novel small specimen testing technique that is currently under development at the University of Nottingham. A small ring of 7175-T7351 aluminum alloy (approximately 10mm in diameter and 2mm in thickness) is loaded between two pins at room temperature, with the local specimen temperature field monitored during monotonic deformation using an infra-red thermal camera. Experimental results are compared for different pin loading rates (namely 0.1mm/s, 1mm/s, and 10mm/s), with particular emphasis placed on localised temperature variations in areas of expected high plasticity. Differences of approximately 0.6°C were observed between 0.1mm/s and 1mm/s tests, with higher temperatures recorded in the latter. Higher temperatures were also noted at small specimen locations associated with localised plasticity. Fundamental thermal material properties are reported for the 7175 alloy in order to facilitate future analysis and heat equation solution efforts (working towards Taylor-Quinney coefficient determination).

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Influence of Stress‐Aging Processing on Precipitates and Mechanical Properties of a 7075 Aluminum Alloy

et al. 2017

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Two‐step stress‐aging tests, as well as pre‐treatment plus stress‐aging experiments, are performed on a 7075 aluminum (Al–Zn–Mg–Cu) alloy. Influences of stress‐aging parameters on mechanical behavior and fracture mechanism are investigated through uniaxial tensile test and fracture morphology analysis. It is revealed that the stress‐aging dramatically influences the mechanical properties and fracture characteristics of the studied alloy, which is contributed to the sensitivity of microstructures to stress‐aging. When the alloy undergoes two‐step stress‐aging, the ultimate tensile strength and yield strength first increase and then decrease with the increased first step stress‐aging temperature, while the elongation first decreases and then increases. For the retrogression pre‐treated plus stress‐aged alloy, the yield strength first increases and then drops with the increased retrogression pre‐treatment time, while the ultimate tensile strength almost remains stable. Furthermore, the elongation continuously increases with the increased retrogression pre‐treatment time. The observation of fracture morphology indicates that the dimple‐type intergranular fracture is the main fracture mechanism for the two‐step stress‐aged and retrogression pre‐treated plus stress‐aged alloys.

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Aging behavior and precipitate characterization of a high Zn-containing Al-Zn-Mg-Cu alloy with various tempers

Cited by 133 publications

References 21 publications

Effect of Zn Concentration on the Microstructure and Mechanical Properties of Al-Mg-Si-Zn Alloys Processed by Gravity Die Casting

Effect of Zn Concentration on the Microstructure and Mechanical Properties of Al-Mg-Si-Zn Alloys Processed by Gravity Die Casting

Investigations into Taylor-Quinney coefficient determination for a 7000 series aluminium alloy using a novel small specimen test technique

Influence of Stress‐Aging Processing on Precipitates and Mechanical Properties of a 7075 Aluminum Alloy

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