Effect of thermo-mechanical processing on quench-induced precipitates morphology and mechanical properties in high strength AA7075 aluminum alloy

Scharifi, Emad; Savacı, Umut; Kavaklioglu, Z. B.; Weidig, Ursula; Turan, Servet; Steinhoff, Kurt

doi:10.1016/j.matchar.2021.111026

Cited by 33 publications

(35 citation statements)

References 74 publications

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“…Under the same aging condition of AA7075, these very fine precipitations have been referred elsewhere in the literature to the η -phase [36]. In addition, coarse precipitates were also observed in the center of the grains (Figure 6a), which were also reported in literature [35,36] for the same aging treatment of AA7075. In Figure 6b, few dislocations were presented in the investigated microstructure.…”

Section: Effect Of Hot Deformation On Microstructuresupporting

confidence: 80%

“…The ultimate tensile strength of 18 MPa was obtained at a very low strain level (Figure 2a). After reaching the peak stress, the tensile curve decreased steadily and an increased true strain to failure was observed compared to those at room temperature reported in the literature for AA7075 [36]. In the present case, a maximum true strain of 0.315 was achieved.…”

Section: Forming Behavior At Elevated Temperaturesupporting

confidence: 69%

“…From this figure, a slight increase in yield and ultimate tensile strength for the hot formed material could be seen. Both curves indicate high material strengths, which can be explained by the formation of the strengthening η -phases, as observed in Figure 3a for AA7075 [36].…”

Section: As-received Microstructure and Mechanical Propertiesmentioning

confidence: 57%

“…The microstructure of the at-2% hot-formed material showed, after aging at 120 °C for 20 h, a homogeneous distribution of very fine particles within the grain structure (Figure 6a,b). Under the same aging condition of AA7075, these very fine precipitations have been referred elsewhere in the literature to the -phase [36]. In addition, coarse precipitates were also observed in the center of the grains (Figure 6a), which were also reported in literature [35,36] for the same aging treat- The hardness distribution after emulation of the thermo-mechanical process route at different deformation degrees of 2, 8, and 10% and different artificial aging (AA) times ranging from 2 to 24 h is shown in Figure 5b.…”

Section: Effect Of Hot Deformation On Microstructurementioning

confidence: 98%

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Influence of Hot Deformation on the Precipitation Hardening of High-Strength Aluminum AA7075 during Thermo-Mechanical Processing

Scharifi

Shoshmina

Biegler

et al. 2021

Metals

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The aim of this work was to investigate the effect of hot deformation on the aging behavior of precipitation-hardenable aluminum alloy AA7075 within a novel thermo-mechanical forming process, in order to gain insight into its precipitation kinetics. For this purpose, the material was formed at 420 °C after undergoing solution treatment to different strain levels ranging from 2% to 10% to obtain different dislocation densities. After undergoing hot deformation, aging at 120 °C with different parameters was carried out to improve the material hardness. The resulting material properties and microstructure evolution were characterized afterward using hardness measurements and a transmission electron microscope (TEM). TEM investigations revealed the formation of very fine particles for the material formed at 2%, as well as at 10%, of formed material, which act as effective barriers to dislocation motion. It was found that the response of artificial aging on the deformation degree in hot forming was less than expected due to the thermally activated mechanisms, leading to a decrease in dislocation density. Therefore, a dramatic increase in material hardness with the increase in hot deformation was not observed.

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Section: Effect Of Hot Deformation On Microstructuresupporting

confidence: 80%

Section: Forming Behavior At Elevated Temperaturesupporting

confidence: 69%

Section: As-received Microstructure and Mechanical Propertiesmentioning

confidence: 57%

Section: Effect Of Hot Deformation On Microstructurementioning

confidence: 98%

See 2 more Smart Citations

Influence of Hot Deformation on the Precipitation Hardening of High-Strength Aluminum AA7075 during Thermo-Mechanical Processing

Scharifi

Shoshmina

Biegler

et al. 2021

Metals

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show abstract

“…Precipitation sequences during aging of a supersaturated solid solution (SSS) and important factors affecting the formation of different types of precipitates were already studied for EN AW 7075 and other alloys of the 7000 series [20][21][22][23]. The generalized precipitation sequence during aging treatment of this alloy is displayed in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Effects of Aging under Stress on Mechanical Properties and Microstructure of EN AW 7075 Alloy

Sajadifar

Krooß

Fröck

et al. 2021

Metals

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In the present study, microstructural and mechanical properties of EN AW 7075 following stress-aging were assessed. For this purpose, properties of stress-aged samples were compared with values obtained for conventionally aged counterparts. It is revealed that the strength and hardness of EN AW 7075 can be increased by the presence of external stresses during aging. Precipitation kinetics were found to be accelerated. The effects of conventional and stress-aging on the microstructure were analyzed using synergetic techniques: the differently aged samples were probed by differential scanning calorimetry (DSC) in order to characterize the precipitation processes. DSC was found to be an excellent screening tool for the analysis of precipitation processes during aging of this alloy with and without the presence of external stresses. Furthermore, using electron microscopy it was revealed that an improvement in mechanical properties can be correlated to changes in the morphologies and sizes of precipitates formed.

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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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Effect of thermo-mechanical processing on quench-induced precipitates morphology and mechanical properties in high strength AA7075 aluminum alloy

Cited by 33 publications

References 74 publications

Influence of Hot Deformation on the Precipitation Hardening of High-Strength Aluminum AA7075 during Thermo-Mechanical Processing

Influence of Hot Deformation on the Precipitation Hardening of High-Strength Aluminum AA7075 during Thermo-Mechanical Processing

Effects of Aging under Stress on Mechanical Properties and Microstructure of EN AW 7075 Alloy

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

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