The Effect of Anodized Coating on Fatigue Strength of Aluminum Alloys.

Shiozawa, Kazuaki; Kobayashi, H.; Terada, Masao; Matsui, Akira

doi:10.1299/kikaia.67.1639

Cited by 9 publications

(6 citation statements)

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“…10 that multiple crack nucleation sites were also found on the fractured surface of the anodized specimens. Shiozawa et al (2001) also demonstrated this phenomenon that number of crack initiation sites increased for the anodized specimens compared to untreated ones. When analyzed thoroughly by SEM, it was found that most of the fatigue cracks for anodized specimens were initiated by pickling pits beneath the coating as shown in Fig.…”

Section: Sem Observationsmentioning

confidence: 62%

Influence of surface treatments on fatigue life of Al 7010 alloy

Shahzad

Chaussumier

Chieragatti

et al. 2010

Journal of Materials Processing Technology

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OATAO is an open access repository that co llects the work of Toulouse researchers and makes it freely available over the web where possible. This is an author -deposited version published in: http://oatao. The objective of the present work is to show the influence of machining and anodizing processes on fatigue life of alloy 7010-T7451. Two different cutting conditions were employed to obtain two different initial surface roughnesses. Degreasing, pickling and anodizing were then carried out. In the as machined condition, surface roughness is clearly effective in reducing fatigue life in this material. As the surface roughness increases fatigue life decreases and this effect is found to be more pronounced in high cycle fatigue where major portion of fatigue life is consumed in nucleating the cracks. Effects of pre-treatments, like degreasing and pickling employed prior to anodizing, on fatigue life of the given alloy were also studied. Fatigue curves showed that pickling had negative impact on fatigue life of specimens while degreasing showed no change in fatigue life. The small decrease in fatigue life of anodized specimens as compare to pickled specimens is attributed to brittle nature and micro-cracking of the coating. Scanning electron microscopic (SEM) examination revealed multi-site crack initiation for the pickled and anodized specimens. SEM examination also showed that pickling process attacked the grain boundaries and the inclusions present on the surface resulting in pits formation. These pits are of primary concern with respect to accelerated fatigue crack nucleation and subsequent anodized coating formation.

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Section: Sem Observationsmentioning

confidence: 62%

Influence of surface treatments on fatigue life of Al 7010 alloy

Shahzad

Chaussumier

Chieragatti

et al. 2010

Journal of Materials Processing Technology

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“…12b) which also reveals that number of fracture steps exists, indicating that fracture has occurred as a consequence of the propagation of several cracks that initiated from film. Shiozawa et al [20] have also demonstrated this phenomenon that number of crack initiation sites increased for the anodized specimens compared to untreated ones. For the anodized specimens, cracks at the multiple initiation sites propagated independently and coalesce with neighboring cracks.…”

Section: Fractographymentioning

confidence: 75%

Effect of sealed anodic film on fatigue performance of 2214-T6 aluminum alloy

Shahzad

Chaussumier

Chieragatti

et al. 2012

Surface and Coatings Technology

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The aim of present study is to investigate the influence of anodic film, grown by sulfuric acid anodizing and sealed in nickel-acetate solution, on fatigue strength of aluminum alloy 2214-T6 by conducting axial fatigue tests at stress ratio 'R' of 0.1 and − 1. The influence of sealed anodic film is to degrade the stress-life (S-N) fatigue performance of the base material at all stress levels. Effects of pre-treatments like degreasing and pickling employed prior to anodizing were also studied and no influence of these pre-treatments was observed on fatigue life. The surface and cross-section observations of anodic film were made by scanning electron microscope (SEM) before and after fatigue tests. The surface observations have revealed cavities which resulted from dissolution of coarse Al 2 Cu particles during anodization and network of micro-cracks on anodic film surface which were initiated as a result of sealing process. Some of these micro-cracks were found to penetrate up-to substrate and have detrimental effect on subsequent fatigue strength. The decrease in fatigue life for anodized-sealed specimens as compared to bare condition has been attributed to decrease in initiation period and multi-site crack initiations. Multi-site crack initiation has resulted in rougher fractured surfaces for the anodized specimens as compared to bare specimens tested at same stress levels.

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“…This multicrack initiation is also responsible for rough fractured surface of the anodized specimen. Shiozawa et al [20] have also demonstrated this phenomenon that number of crack initiation sites increased after the anodizing treatment. For the pickled and anodized specimens, cracks at the multiple initiation sites propagated independently and coalesce with neighbouring cracks.…”

Section: (A) (B)mentioning

confidence: 77%

Surface characterization and influence of anodizing process on fatigue life of Al 7050 alloy

et al. 2011

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The present study investigates the influence of anodizing process on fatigue life of aluminium alloy 7050-T7451 by performing axial fatigue tests at stress ratio 'R' of 0.1. Effects of pre-treatments like degreasing and pickling employed prior to anodizing on fatigue life were studied. The post-exposure surface observations were made by scanning electron microscope (SEM) to characterize the effect of each treatment before fatigue testing. The surface observations have revealed that degreasing did not change the surface topography while pickling solution resulted in the formation of pits at the surface. Energy dispersive spectroscopy (EDS) was used to identify those constituent particles which were responsible for the pits formation. These pits are of primary concern with respect to accelerated fatigue crack initiation and subsequent anodic coating formation. The fatigue test results have shown that pickling process was detrimental in reducing the fatigue life significantly while less decrease has been observed for anodized specimens. Analyses of fracture surfaces of pickled specimens have revealed that the process completely changed the crack initiation mechanisms as compared to non-treated specimens and the crack initiation started at the pits. For most of the anodized specimens, fatigue cracks still initiated at the pits with very few cracks initiated from anodic coating. The decrease in fatigue life for pickled and anodized specimens as compared to bare condition has been attributed to decrease in initiation period and multi-site crack initiations. Multi-site crack initiation has resulted in rougher fractured surfaces for the pickled and anodized specimens as compare to bare specimens tested at same stress levels.

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The Effect of Anodized Coating on Fatigue Strength of Aluminum Alloys.

Cited by 9 publications

References 0 publications

Influence of surface treatments on fatigue life of Al 7010 alloy

Influence of surface treatments on fatigue life of Al 7010 alloy

Effect of sealed anodic film on fatigue performance of 2214-T6 aluminum alloy

Surface characterization and influence of anodizing process on fatigue life of Al 7050 alloy

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