Effect of anodizing treatment on the very high cycle fatigue behavior of 2A12-T4 aluminum alloy

Coupled effects of substrate microstructure and sulphuric acid anodizing on fatigue life of a 2017A aluminum alloy

“…The anodic film would be expected to influence more significantly the fatigue crack nucleation stage and hence fatigue lives, at low stresses. The obtained results are in agreement with those of Nie et al [19].…”

“…The SEM examination showed that in some regions, partial delamination of the anodic film occurred along many areas, leading to the subsequent fracture of the material at the interface, as can be seen in Figs. 12a, b and c, in agreement with the findings earlier reported by Nie et al [19]. The delamination of the film observed in Fig.…”

“…This discrepancy classically appears to be associated to the brittle and porous nature of the oxide layer [11][12][13], as well as the tensile residual stresses induced during the anodizing process [13][14][15]. Much of the available literature provides evidence that the reduction in fatigue life is not only due to the well-known brittle properties of the aluminum oxide, but also to the film thickness [15][16][17][18], type of anodizing process [14,15,18,19], surface pretreatment prior anodizing [20][21][22] and sealing treatment after anodizing [23,24]. However, the reported data available in the literature regarding the combined effect of substrate microstructure and anodizing on the reduction in fatigue life is quite limited.…”

The role of peening processes as a pre‐treatment to anodizing on fatigue behavior of aircraft aluminum alloy

“…4 In particular, it has been widely demonstrated in the scientific literature that the presence of the anodic layer has a significant influence on the fatigue behavior of materials, and this was attributed mainly to the following reasons: firstly, the brittleness and the presence of porosity that easily cracks under cyclic tensile loading and the strong adhesion of the anodic layer to the substrate; secondly, the occurrence of tensile residual stresses due to the elastic incompatibility between the anodic layer and the base material surface; and lastly, the formation of pitlike defects that could act as preferential sites for the nucleation of fatigue cracks. [5][6][7][8][9][10][11][12][13][14][15] From a structural point of view, it is crucial to ensure both corrosion resistance and fatigue properties in components. To achieve this, the anodizing process must be optimized to meet design requirements regarding the thickness and morphology of the anodic layer.…”

On the anelasticity and fatigue fracture entropy in high-cycle metal fatigue

“…Although the level of stress in an HCF test remains within the elastic limit, the material experiences local micro-scale plastic deformations [1][2][3]. As a result, metallic materials do not exhibit truly infinite fatigue life [4][5][6][7][8][9]. Therefore, each load cycle must necessarily introduce a certain amount of irreversible degradation, albeit small, in the material regardless of the amplitude of stress [10][11][12][13].…”