The Effects of Retrogression and Reaging on Aluminum Alloy 2099 (C458)

Ward, N.; Tran, Anh Phuong; Abad, A.; Lee, E. W.; Hahn, M.; Fordan, E.; Es‐Said, O.S.

doi:10.1007/s11665-010-9737-7

Cited by 11 publications

(2 citation statements)

References 8 publications

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“…The hardness of the treated specimens is quite below than that of T6 and T7 conditions. It is noted in previous studies [31][32][33] that the mechanical properties increase for a limited retrogression time; however, beyond a threshold time, they continuously decrease as a function of retrogression time. According to Ferrer et al, 27 in the RRA treatment of AA7075 at a retrogression temperature of 200 C, maximum hardness is achieved at the retrogression time of approximately 30 min.…”

Section: Resultsmentioning

confidence: 99%

Fatigue and corrosion behavior of in-service AA7075 aircraft component after thermo-mechanical and retrogression and re-aging treatments

Gürgen

Saçkesen

Kuşhan

2018

Proceedings of the IMechE

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Fatigue crack growth and corrosion are the two important failure mechanisms for aircraft structural components and, therefore, various treatments have been developed to improve the fatigue and corrosion resistance of aircraft materials. In the present study, thermo-mechanical and retrogression and re-aging treatments were applied to AA7075T7352 specimens, which were extracted from a nearly 40 years in-service F-4 Phantom component. The in-service component was selected in order to observe the influence of thermo-mechanical and retrogression and re-aging treatments on the properties of a used aircraft material and it was expected that the service life of the material is extended in the maintenance stage. In the experimental work, electrical, mechanical, fatigue crack growth, and corrosion tests were carried out using the specimens with T7352 (as-received), thermo-mechanical and retrogression and re-aging conditions. Based on the results, fatigue crack growth resistance of the material benefited from the thermo-mechanical and retrogression and re-aging treatments; however, both treatments lowered the corrosion resistance of the material.

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Section: Resultsmentioning

confidence: 99%

Fatigue and corrosion behavior of in-service AA7075 aircraft component after thermo-mechanical and retrogression and re-aging treatments

Gürgen

Saçkesen

Kuşhan

2018

Proceedings of the IMechE

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“…After the paint-bake, a significant aging response is observed and the strength of the warm formed PA samples approach that of the RT T6 condition (seen in Figure 4 d-f). The observed drop and subsequent recovery in strength may be indicative of retrogression and re-aging [22] for the 150°C WF+PB cycle.…”

Section: Secondary Aged Tensile Properties Of Pa and T6 Tempers Follo...mentioning

confidence: 89%

Effect of Initial Temper on the Warm Forming Characteristics of a High Strength 7000-series Al-Zn-Mg-Cu Alloy

DiCecco

Ciano

Butcher

et al. 2022

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

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In this work, the formability of a developmental 7000-series copper containing aluminium alloy was assessed at room temperature (RT), 150°C, 175°C and 200°C in pre-aged (PA), peak-aged (T6) and overaged (T76) tempers using Nakazima tests with stereoscopic digital image correlation (DIC) strain measurement. The limit strains were identified using a novel curvature-based approach to detect the formation of an acute neck. The tensile mechanical properties in these warm forming processing routes were characterized with and without a paint bake cycle. Finally, a thermo-mechanical tensile simulator was used to evaluate the constitutive response of the PA and T76 tempers as a function of strain-rate and time at 175°C. Formability results found the selected PA temper to have a good room temperature formability and a mild positive response to the selected warm-forming cycles. The T6 and T76 tempers both exhibited increases in formability in response to warm forming. The PA temper had a significant positive response to short-duration warm forming and subsequent paint baking, with the yield strength increasing from 420 MPa to 512 MPa following this thermal cycle. For the T6 temper, the warm-forming cycle showed a trend characteristic of retrogression and re-aging, with the warm-forming cycle dropping the yield strength from 566 MPa to 534 MPa and the subsequent paint-bake re-aging to 554 MPa. The effect of aging during pre-heating prior to warm forming on the warm constitutive response of the PA and T76 tempers was also investigated. Both tempers exhibited rather different aging responses to short-duration thermal cycles. In the PA temper, this manifested as an increase in at-temperature yield strength and loss of hardening rate. In contrast, the T76 temper exhibited a drop in strength since this temper is already over-aged prior to warm forming. Both the PA and T76 tempers showed comparable at-temperature strain-rate sensitivity.

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Effect of Double Aging on the Toughness and Precipitation Behavior of a Novel Aluminum-Lithium Alloy

Liang

et al. 2015

J. of Materi Eng and Perform

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Precipitation behavior and mechanical properties of a novel aluminum-lithium alloy were investigated during a double-aging treatment to obtain superior combination of strength and plasticity. The double-aging process, involving subsequent high to low temperature treatments, was applied to strengthen the alloy. Transmission electron microscopy was used to characterize the precipitation behavior of the alloy, while tensile and tear tests were performed to evaluate the mechanical properties. The results indicated that the samples double aged at (165°C, 10 h) + (140°C, 35 h) possessed a desired combination of strength, plasticity, and toughness. T 1 phases were observed to nucleate preferentially at the defects during the first (primary) aging step. During the second (secondary) step of aging, these phases grew further and promoted the formation of new precipitates. Compared to the single-aging treatment, the double-aging treatment effectively prevents coarsening of T 1 , which is beneficial in improving the plasticity and toughness of the alloy.

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The Effects of Retrogression and Reaging on Aluminum Alloy 2099 (C458)

Cited by 11 publications

References 8 publications

Fatigue and corrosion behavior of in-service AA7075 aircraft component after thermo-mechanical and retrogression and re-aging treatments

Fatigue and corrosion behavior of in-service AA7075 aircraft component after thermo-mechanical and retrogression and re-aging treatments

Effect of Initial Temper on the Warm Forming Characteristics of a High Strength 7000-series Al-Zn-Mg-Cu Alloy

Effect of Double Aging on the Toughness and Precipitation Behavior of a Novel Aluminum-Lithium Alloy

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