Prediction of creep–fatigue crack growth rates in inert and active environments in an aluminium alloy

Gardin, C.; Odemer, Grégory; Guiffard, Benoît; Koffi, E.; Journet, Bertrand

doi:10.1016/j.ijfatigue.2009.02.017

Cited by 21 publications

(25 citation statements)

References 10 publications

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“…These presumptions agree with some of the research reported in the literature, but still, there is controversy about the effect of frequency on the fatigue response, as shown in Section 1.1. For example, our findings agree with results from low frequency investigations for Al alloy RR58 at 423 K [25] and for AA 2650-T6 at 175˝C [26], pointing out that fatigue life is sensitive to frequency and that it increases with loading frequency. There is agreement also with the results for E319 cast Al alloy at 423 and 523 K, pointing out that fatigue life at 20 kHz was longer than at 75 Hz [14].…”

Section: Effect Of Internal Friction On Fatigue Strengthsupporting

confidence: 90%

“…This hypothesis is in line with research by Henaff et al [26] and Nikbin and Radon [25], suggesting the existence of a critical value of loading frequency below which, for a given temperature, the material exhibits a static-like response (relaxed case), crack growth is sensitive to frequency and static creep dominates instead of pure fatigue mechanisms.…”

Section: Temperature Dependence Of the Storage Modulussupporting

confidence: 89%

“…This shows that creep damage might occur during loading at low frequency, in accordance with the findings in [25]. Henaff et al [26] reported also that, for a given temperature, CFCG is unaffected by frequency above a critical value of the loading frequency (see Figure 12b in [26]). Below, CFCG is inversely proportional to excitation frequency, i.e., a time-dependent crack growth processes take place.…”

Section: Influence Of the Loading Frequency On The Fatigue Response Osupporting

confidence: 82%

“…On the other hand, Henaff et al [26] analyzed creep crack growth (CCG) rates, FCG rates and creep-fatigue crack growth (CFCG) rates of AA 2650-T6 at 293, 403 and 448 K, for frequencies of 0.05 and 20 Hz. The objective was to enable the prediction of crack growth resistance of that alloy under very low frequency loading at elevated temperatures.…”

Section: Influence Of the Loading Frequency On The Fatigue Response Omentioning

confidence: 99%

“…Furthermore, by integration of a universal version of a modified superposition model, the effects of temperature, frequency and the environment on the S-N curve of this alloy can be predicted, and it is possible also to extrapolate ultrasonic data to conventional fatigue behavior [14]. Henaff et al [26] concluded that the temperature has almost no influence on FCG rates for AA 2650-T6, after conducting tests at 293, 403 and 448 K and frequencies of 0.05 and 20 Hz. Amiri and Khonsari [4] state that the initial slope of the temperature rise due to hysteresis heating observed at the beginning of fatigue tests is a characteristic of metals.…”

Section: Influence Of Temperature On the Fatigue Response Of Al Alloysmentioning

confidence: 99%

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Onset Frequency of Fatigue Effects in Pure Aluminum and 7075 (AlZnMg) and 2024 (AlCuMg) Alloys

Rojas

Crespo

2016

Metals

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Abstract:The viscoelastic response of pure Al and 7075 (AlZnMg) and 2024 (AlCuMg) alloys, obtained with a dynamic-mechanical analyzer (DMA), is studied. The purpose is to identify relationships between the viscoelasticity and fatigue response of these materials, of great interest for structural applications, in view of their mutual dependence on intrinsic microstructural effects associated with internal friction. The objective is to investigate the influence of dynamic loading frequency and temperature on fatigue, based on their effect on the viscoelastic behavior. This research suggests that the decrease of yield and fatigue behavior reported for Al alloys as temperature increases may be associated with the increase of internal friction. Furthermore, materials subjected to dynamic loading below a given threshold frequency exhibit a static-like response, such that creep mechanisms dominate and fatigue effects are negligible. In this work, an alternative procedure to the time-consuming fatigue tests is proposed to estimate this threshold frequency, based on the frequency dependence of the initial decrease of the storage modulus with temperature, obtained from the relatively short DMA tests. This allows for a fast estimation of the threshold frequency. The frequencies obtained for pure Al and 2024 and 7075 alloys are 0.001-0.005, 0.006 and 0.075-0.350 Hz, respectively.

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Section: Effect Of Internal Friction On Fatigue Strengthsupporting

confidence: 90%

Section: Temperature Dependence Of the Storage Modulussupporting

confidence: 89%

Section: Influence Of the Loading Frequency On The Fatigue Response Osupporting

confidence: 82%

Section: Influence Of the Loading Frequency On The Fatigue Response Omentioning

confidence: 99%

Section: Influence Of Temperature On the Fatigue Response Of Al Alloysmentioning

confidence: 99%

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Onset Frequency of Fatigue Effects in Pure Aluminum and 7075 (AlZnMg) and 2024 (AlCuMg) Alloys

Rojas

Crespo

2016

Metals

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A New Method to Characterize and Model Stress-Relaxation Aging Behavior of Aluminum Alloys Under Age Forming Conditions

Shi

2022

Metall Mater Trans A

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A new method that utilises theories of thermally activated deformation and repeated transient stress-relaxation tests has been proposed and validated in this study for the characterisation and modelling of the stress-relaxation ageing (SRA) behaviour of aluminium alloys and its dependence on stress and temperature. Using the new method, key deformation-related variables, i.e. stress components, activation volume and energy, of the aerospace grade heattreatable aluminium alloy AA7B04 have been obtained as a function of ageing temperature (388, 413 and 438 K), stress (both elastic and plastic) and SRA time (up to 4 h). It has been found that the apparent activation energy Qa of the material remains constant in the elastic region but decreases with increasing strain in the plastic region, and also decreases with increasing temperature for all initial loading stresses. These characteristics contribute to a much higher degree of stress-relaxation in the plastic region and at higher temperatures than in the elastic region and/or at lower temperatures. The obtained changing activation volume V and Qa indicate that the deformation rate is controlled by forest dislocation interactions in the elastic region (V decreases from over 200b 3 to less than 100b 3 ), and by a cross-slip mechanism at high stress levels in the plastic region (V decreases to a few tens of b 3 ). Based on these theories and results, a novel and simple constitutive model has been proposed, with which the stressrelaxation behaviour of AA7B04 at different ageing temperatures (388 to 448 K), pre-loaded from elastic to plastic regions for up to 16 h has been successfully predicted. The proposed model eliminates the limitations of conventional SRA models which mainly deal with elastic loading and isothermal conditions, and provides a foundation to effectively predict the springback after advanced non-isothermal SRA forming of aluminium alloy structures in the aerospace industry.

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Effect of Hold Time on Crack Growth Behavior of Pb-Containing and Pb-Free Solders

Fakpan

Otsuka

Mutoh

et al. 2012

Journal of Elec Materi

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Prediction of creep–fatigue crack growth rates in inert and active environments in an aluminium alloy

Cited by 21 publications

References 10 publications

Onset Frequency of Fatigue Effects in Pure Aluminum and 7075 (AlZnMg) and 2024 (AlCuMg) Alloys

Onset Frequency of Fatigue Effects in Pure Aluminum and 7075 (AlZnMg) and 2024 (AlCuMg) Alloys

A New Method to Characterize and Model Stress-Relaxation Aging Behavior of Aluminum Alloys Under Age Forming Conditions

Effect of Hold Time on Crack Growth Behavior of Pb-Containing and Pb-Free Solders

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