High- and very high-cycle plain fatigue resistance of shot peened high-strength aluminum alloys: The role of surface morphology

Benedetti, M.; Fontanari, V.; Bandini, Michele; Savio, Enrico

doi:10.1016/j.ijfatigue.2014.07.002

Cited by 95 publications

(49 citation statements)

References 56 publications

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“…This treatment proved to confer better fatigue performance as compared with samples peened using larger shots [50,51]. Three sets of XRD measurements were carried out in the centre of the frontal surface of plain samples to investigate the far-field in-depth residual stress profile, as reported in [12] using an AST X-Stress 3000 X-ray diffractometer operated with Cr Kα radiation. The region of interest was limited by a collimator to 1 mm 2 in area.…”

Section: Methodsmentioning

confidence: 99%

“…These measurements rely on the assumption that the gentle mechanical removal of a tiny surface layer does not significantly affect the RS distribution. This has been experimentally validated in [12], where similar shot peened samples were tribofinished to remove a material surface layer of 5÷10 μm thickness from the entire frontal surface. XRD measurements on the tribofinished surface revealed that the material removal exposes on the surface the RS that was present at the corresponding depth prior to polishing.…”

Section: Methodsmentioning

confidence: 99%

“…The stacks of SEM images were aligned using the align slices module Fig. 7 Depth profile of residual stress, σ x , in bead-peened Al-7075-T651 measured by AST XStress 3000 X-ray diffractometer [12]. Note: Residual stresses are measured on x-y plane in Figs.…”

Section: Methodsmentioning

confidence: 99%

“…Shot peening conducted at low intensities with small beads is more effective in incrementing the fatigue resistance as compared to more intense treatments with larger shots [12], since it causes a lower surface roughening and induces the maximum compressive residual stress as close as possible to the surface. However current study shows that in the superficial surface layer tensile residual stresses are present (Fig.…”

Section: Surface Residual Stress Measurement Between the Notchesmentioning

confidence: 99%

“…Therefore, in recent years, there has been increasing interest in explicitly including the effects of SP process into life assessment models rather than considering SP simply as an additional safety factor [9]. Specifically, RS produced by shot peening are incorporated into multiaxial fatigue criteria, sometimes in combination with critical distance approaches [7,10,11], or into damage tolerant approaches [12][13][14]. In the former, the RSs are treated as mean biaxial stresses superimposed on the stress field produced by external loading, in the latter case, the RSs are included as R-ratio and crack closure effects.…”

Section: Introductionmentioning

confidence: 99%

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High Spatial Resolution Evaluation of Residual Stresses in Shot Peened Specimens Containing Sharp and Blunt Notches by Micro-hole Drilling, Micro-slot Cutting and Micro-X-ray Diffraction Methods

et al. 2016

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The moderately high lateral RS gradients (on the order of tens of MPa/μm) near shot peened notches in conjunction with the shallow treatment depth (some hundreds of microns) limit the application of far-field and/or high resolution synchrotron diffraction residual stress measurement techniques. Recently proposed Focused Ion Beam -Scanning Elecron Microscope -Digital Image Correlation (FIB-SEM-DIC) based micro mechanical stress relaxation methods for the measurement of residual stress at the micron scale became suitable techniques for local evaluation of residual stresses and stress gradients in shot peened specimens. In this paper ultra-high resolution (~0.5-0.8 μm depth and 5-10 μm lateral resolution) mechanical relaxation stress measurements were used to evaluate the stress variation local to individual peening dimples in ceramic (60-120 μm diameter beads) shot peened Al-7075-T651 double notched samples having 0.15, 0.5 and 2.0 mm radii using Micro-Hole Drilling (μHD), Micro-Slot Cutting (μSC) and micro X-ray Diffraction (μXRD) methods. The micron-sized sampling volumes enabled the stress to be evaluated in individual impact craters (dimples) showing significant point-to-point variation (~+/−150 MPa) (with certain dimples even recording tensile stresses). After around 30 μm of layer removal the heavily deformed region had largely been removed and the stress profile became much more homogeneous. At this depth the μHD and μSC results were in good accord with those from μXRD measurements which sample over a much larger volume (~40 μm depth × 50 μm laterally) showing an in-plane compressive stress of around 150 MPa far from the notches with the residual stress rising to about 200 MPa at a blunt (2 mm) notch and 500 MPa for a sharp (0.15 mm) one. Further, these recorded variations of residual stresses were correlated with microstructural features, e.g. grains, networks of sub-surface cracks, intermetallics and highly deformed sub-surface regions, revealed by large volume Serial Sectioning Tomography using Plasma Xe + Focus Ion Beam -Scanning Electron Microscope (PFIB-SEM), EDS and EBSD maps. This allowed for the first time characterize large volume (100 × 66 × 30 μm 3 ) of shot peened regions with resolution of dozens of nanometers and correlate residual stress depth profiles with 3D microstructural features. Finally, in (Benedetti et al. 2016, Int. J. Fatigue) these RS measurements are used to reconstruct the RS field through finite element (FE) analyses.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Surface Residual Stress Measurement Between the Notchesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

High Spatial Resolution Evaluation of Residual Stresses in Shot Peened Specimens Containing Sharp and Blunt Notches by Micro-hole Drilling, Micro-slot Cutting and Micro-X-ray Diffraction Methods

et al. 2016

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Enhancing the Structural Performance of Lightweight Metals by Shot Peening

Bagherifard

2019

Adv Eng Mater

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Lightweight metals and metal alloys provide the opportunity to fulfill the exigent weight‐saving requirements for structural components. Mechanical surface treatments, in particular, shot peening and other varieties of impact‐based surface treatments are found to be able to significantly promote the structural application of lightweight metals through enhancing their mechanical performance. Moreover, these treatments have substantiated a notable prospect to modulate the surface–environment interaction of the treated material, bringing in original functionalities in multiple fields of application. Herein, the current state‐of‐the‐art in the implementation of shot peening‐based surface treatments is reviewed regarding lightweight metallic materials. The recent advancements are described focusing on the foremost characteristics of the major lightweight metals commonly used in aerospace, automotive, and biomedical sectors. Emergent applications and the existing challenges are highlighted. Lastly, future perspectives on tailoring the effects of shot peening‐based mechanical surface treatments to boost the appeal of lightweight metals as structural components are provided.

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Effect of Surface Mechanical Attrition Treatment on Surface Topography and Dry Sliding Wear Performance of AA7075‐T6

Yarar,

Erturk,

Karabay

2024

Adv Eng Mater

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Surface roughness significantly impacts the service life of materials, particularly in relation to fatigue and wear behavior. This study investigates the effects of surface mechanical attrition treatment (SMAT) on the wear performance and surface topography of AA7075‐T6 aluminum alloy. Experimental investigations are conducted using a specially designed vibration table to apply SMAT at low speeds, varying shot amount, and shot diameter. Surface roughness is measured using a 3D optical profilometer, and wear performance is evaluated through friction coefficient, wear rate, and microstructural analysis via scanning electron microscope. The results highlight several key findings. First, SMAT demonstrates the capability to yield smoother surfaces compared to equivalent processes, enhancing performance and applicability in engineering contexts. Second, SMATed samples exhibit increased surface roughness compared to untreated samples, underscoring the influence of SMAT on surface topography and its potential implications for wear resistance and frictional behavior. The comparative analysis shows that SMAT treatment increases surface roughness from 0.14 μm to a maximum of 0.24 μm. Finally, a notable reduction in friction coefficient, up to 22%, is observed in SMATed AA7075‐T6 samples, indicating the effectiveness of SMAT in improving tribological properties and enhancing component longevity subjected to frictional forces.

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High- and very high-cycle plain fatigue resistance of shot peened high-strength aluminum alloys: The role of surface morphology

Cited by 95 publications

References 56 publications

High Spatial Resolution Evaluation of Residual Stresses in Shot Peened Specimens Containing Sharp and Blunt Notches by Micro-hole Drilling, Micro-slot Cutting and Micro-X-ray Diffraction Methods

High Spatial Resolution Evaluation of Residual Stresses in Shot Peened Specimens Containing Sharp and Blunt Notches by Micro-hole Drilling, Micro-slot Cutting and Micro-X-ray Diffraction Methods

Enhancing the Structural Performance of Lightweight Metals by Shot Peening

Effect of Surface Mechanical Attrition Treatment on Surface Topography and Dry Sliding Wear Performance of AA7075‐T6

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