Formability of 7000 aluminum alloys in warm and hot forming condition

Behrens, Bernd‐Arno; Hübner, Sven; Vogt, H.

doi:10.1088/1757-899x/418/1/012027

Cited by 10 publications

(6 citation statements)

References 10 publications

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“…High-strength aluminum alloys show limited formability and, thus, pronounced springback after forming; however, a thermomechanical process is expected to reduce springback. [5,21] Figure 4 shows two formed geometries after the cold and hot forming-die quenching process. The target angle being 93°, the T6-condition hat-shaped profile exhibits low-dimensional accuracy, Figure 4a, while the hot-formed and die-quenched SHT profile, Figure 4b, reveals almost no springback.…”

Section: General Considerationmentioning

confidence: 99%

“…As a result, several temperature-assisted forming processes have been developed, either softening the material for cold forming through an appropriate pretreatment [1,2] or using elevated forming temperatures. [3][4][5][6][7][8] Quite recently, a hot forming-quenching (HFQ) integrated process has been developed by Jiang et al for forming high-strength Al alloys. [4] The basic principle is to finalize the forming process before any aginginduced strengthening.…”

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confidence: 99%

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Functionally Graded AA7075 Components Produced via Hot Stamping: A Novel Process Design Inspired from Analysis of Microstructure and Mechanical Properties

et al. 2023

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Herein, functionally graded AA7075 components manufactured via hot stamping are investigated by focusing on the effect of different process variables on localized microstructure evolution. To realize gradation through stamping, an active tool is designed and applied. The design of experiments allows to assess the impact of transfer time from the furnace to the tool, quenching time in the tool, and final quenching media. Related characteristics of mechanical properties throughout the hat‐shaped profile are assessed via hardness and tensile tests. As expected, the sections of the samples formed in the cooled part of the tool are characterized by higher mechanical strength following subsequent aging, while sections formed in the heated part exhibit higher ductility. Moreover, the microstructural analysis reveals that fine precipitates with minimum interparticle distances only form in the cooled section of the samples. Increasing the tool temperature at the heated side to 350 °C results in the formation of coarse precipitates in the grain interior and along the grain boundaries. A sharp gradient in terms of microstructural and mechanical properties is found between these conditions. After reducing the transfer time, an increased volume fraction of fine precipitates leads to further improvements in hardness and mechanical strengths.

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Section: General Considerationmentioning

confidence: 99%

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confidence: 99%

Functionally Graded AA7075 Components Produced via Hot Stamping: A Novel Process Design Inspired from Analysis of Microstructure and Mechanical Properties

et al. 2023

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“…High-strength aluminum alloys of the 6xxx and 7xxx series permit the realization of lightweight design and fulfill these demands. Due to their limited formability, high-strength aluminum alloys can only be formed without failure using thermally supported forming methods [1]. In particular, the so-called Hot Form and Quench (HFQ ® ) process first introduced by Garret et al offers beneficial forming and component properties [2].…”

Section: Introductionmentioning

confidence: 99%

Development of a novel forming tool for the production of high-strength aluminum components with tailored properties

Rigas,

Merklein

2024

IOP Conf. Ser.: Mater. Sci. Eng.

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Because of growing environmental and technical requirements, the efficient manufacturing of components with tailored properties using recyclable materials is mandatory. The combination of high-strength aluminum alloys and thermal-assisted forming operations is an innovative method for the production of components with varying mechanical properties. By locally adjusting the cooling rates during a thermo-mechanical forming operation, it is possible to modify the microstructure and precipitation conditions. A subsequent aging operation causes different microstructural and mechanical characteristics. This allows both deep-drawing and adjustment of the component properties in one single step. For this reason, this contribution focuses on the production of components with tailored properties. With the aid of a non-contact measuring system, previous investigations have proved that mechanical material properties can be adapted during a forming process by adjusting the cooling rates. In this contribution, this knowledge is transferred to a novel temperature-controlled rectangular cup tool. A variation of the local tool temperature and holding duration in the tool will be carried out. Then, the mechanical and microstructural properties of the manufactured components will be characterized through hardness and DSC investigations. In addition, the influence of different tool temperatures on the component temperature, the sheet thickness distribution and process forces will be investigated. As a result, it has been demonstrated that mechanical, process-related and geometric advantages can be achieved by using locally temperature-controlled forming tools.

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“…High-strength aluminum alloys of the 6000 and 7000 series have increasingly raised the interest of the automotive industry due to their high strength to weight ratio and stiffness to weight ratio, improved corrosion resistance, joinability and recyclability [ 1 ]. However, since the forming capacity is limited for the higher-strength aluminum alloys of the 7000 series at room temperature, various manufacturing technologies have recently been developed for processing at warm or hot forming temperatures [ 2 ]. In particular, the combination of forming and quenching processes is considered here, in which a solution-annealed blank is simultaneously formed in a cooled die and quenched.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigations on Thermal Forming Limit Testing with Local Inductive Heating for Hot Forming of AA7075

et al. 2021

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Forming 7000-series aluminum alloys under elevated temperatures is particularly attractive due to their increased formability. To enable process design by finite element simulation for hot forming, strain-based criteria, such as temperature-dependent forming limit diagrams (TFLD), can be consulted to assess forming feasibility. This work numerically investigates the extent to which in-plane experimental concepts with partial inductive heating are suitable for detecting discrete failure points in TFLD. In particular, an alternative to the currently widely used thickness-reduced specimen geometries was created for cruciform specimens under biaxial tension. First, the temperature-dependent and strain-rate-dependent flow behavior was investigated for AA7075 under uniaxial tension. A heat source model for partial inductive heating was inversely parameterized based on heating experiments. Subsequently, the test procedures were simulated with different specimen geometries under discrete strain conditions. Different concepts were discussed for deriving a suitable specimen shape for the biaxial tension case, and the influence of different notch and slot forms were shown. The simulations showed that partial inductive heating was suitable to induce failure situations, thus creating TFLDs. For the biaxial tension case, a sufficiently large temperature gradient was required to use cruciform specimens without thickness reduction.

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Formability of 7000 aluminum alloys in warm and hot forming condition

Cited by 10 publications

References 10 publications

Functionally Graded AA7075 Components Produced via Hot Stamping: A Novel Process Design Inspired from Analysis of Microstructure and Mechanical Properties

Functionally Graded AA7075 Components Produced via Hot Stamping: A Novel Process Design Inspired from Analysis of Microstructure and Mechanical Properties

Development of a novel forming tool for the production of high-strength aluminum components with tailored properties

Numerical Investigations on Thermal Forming Limit Testing with Local Inductive Heating for Hot Forming of AA7075

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