Fatigue strength improvement of an aluminum alloy with a crack-like surface defect using shot peening and cavitation peening

Takahashi, Koji; Osedo, Hiroko; Suzuki, Takaya; Fukuda, Shinsaku

doi:10.1016/j.engfracmech.2018.02.013

Cited by 70 publications

(38 citation statements)

References 24 publications

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“…Similar effects of SP and needle peening have been reported in various other materials for the rendering of harmless surface defects . Specifically, Takahashi et al clarified that semicircular slits with depths of 0.1 mm in the aluminum alloy A7075‐T651 could be rendered harmless by performing SP . Several studies have shown that the propagation of fatigue cracks in aluminum alloys is delayed by applying LP at the tip of these cracks .…”

Section: Introductionmentioning

confidence: 60%

“…[16][17][18] Specifically, Takahashi et al clarified that semicircular slits with depths of 0.1 mm in the aluminum alloy A7075-T651 could be rendered harmless by performing SP. 19 Several studies have shown that the propagation of fatigue cracks in aluminum alloys is delayed by applying LP at the tip of these cracks. 6,[19][20][21][22] The effects of LP on metals introduced with artificial defects has also been studied.…”

Section: Introductionmentioning

confidence: 99%

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Effects of laser peening on the fatigue strength and defect tolerance of aluminum alloy

Takahashi

Kogishi

Shibuya

et al. 2020

Fatigue Fract Eng Mat Struct

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The effects of laser peening (LP) on the bending fatigue strength of the 7075‐T651 aluminum alloy were investigated. Accordingly, the defect tolerance of the aluminum alloy subjected to LP is discussed on the basis of fracture mechanics. The results indicate that a deeper compressive residual stress was induced by LP compared with the case of shot peening (SP). The fatigue strengths increased when both peening types were used. Semicircular slits with depths less than 0.4 and 0.1 mm were rendered harmless on the basis of the applications of LP and SP, respectively. The apparent threshold stress intensity factor range ΔKth,ap increased by approximately five and two times owing to LP and SP, respectively. The increase of the ΔKth,ap was caused by the compressive residual stress induced by the peening. The Kitagawa‐Takahashi diagram of the laser‐peened specimens shows that the defect tolerance of the aluminum alloy was improved by LP.

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Section: Introductionmentioning

confidence: 60%

Section: Introductionmentioning

confidence: 99%

Effects of laser peening on the fatigue strength and defect tolerance of aluminum alloy

Takahashi

Kogishi

Shibuya

et al. 2020

Fatigue Fract Eng Mat Struct

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“…The SP process is further categorized based on the size, shape, material, intensity of peening medium during blasting, and associated peening mechanisms. Apart from the conventional SP, the other popular methods include fine particle SP, cavitation peening, water jet peening, and shock peening . The gentle SP with finer medium does not cause any significant increase in surface roughness; the compressive residual stresses generated are capable of enhancing the fatigue life of Al alloys .…”

Section: Introductionmentioning

confidence: 96%

“…Apart from the conventional SP, the other popular methods include fine particle SP, cavitation peening, water jet peening, and shock peening. 18,19 The gentle SP with finer medium does not cause any significant increase in surface roughness; the compressive residual stresses generated are capable of enhancing the fatigue life of Al alloys. 20,21 However, the shallower peening depth created through such gentle SP gets consumed during the formation of thicker MAO coating, and therefore the overall benefit of peening is lost.…”

Section: Introductionmentioning

confidence: 99%

Enhancing the high cycle fatigue life of high strength aluminum alloys for aerospace applications

Krishna

Madhavi

Sahithi

et al. 2018

Fatigue Fract Eng Mat Struct

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Hard anodized (HA) and micro arc oxidation (MAO) coatings of identical thickness were deposited on two different high strength aluminum (Al) alloys namely, 2024‐T3 and 7075‐T6. Further, as received Al alloys were also subjected to shot peening (SP) to induce subsurface compressive residual stresses followed by the MAO coating deposition (SP + MAO). The average velocity of particle‐in‐flight during the SP process was measured and utilized to calculate the kinetic energy of the peening particles. The bare and coated alloys were subjected to completely reversed stress (R = −1) rotating beam high cycle fatigue tests at five different stress levels. In addition, the bare and coated alloys were also evaluated for their tensile properties, elemental composition, phase constituents, surface, and cross‐sectional morphologies including the surface roughness (Ra, Rz) and correlated the same with the corresponding fatigue behavior. Irrespective of substrate alloy composition and stress levels investigated, the duplex SP + MAO treatment resulted in significant fatigue life enhancement over and above the fatigue life of corresponding bare (not shot peened) Al alloy, while the hard anodized and plain MAO (both without prior shot peening) continue to exhibit significant fatigue debit. Driven by the compressive residual stresses present beneath the subsurface region of SP + MAO coating interface, fractured surface examination of SP + MAO coatings clearly highlights the crack‐branching associated multiple crack deflection as the predominant operative mechanism responsible for diminishing the crack growth rate and therefore enhance the fatigue life as compared with the near linear crack extension without significant deflections leading to relative premature failure of plain MAO coated alloys.

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“…It is known that surface treatment is one of the effective methods to improve fatigue strengths of structural alloys. For example, mechanical peening processes such as shot peening (Masaki et al, 2003), laser peening (Masaki et al, 2007) and cavitation peening (Takahashi et al, 2018) could increase fatigue strengths of Al alloys, by increasing surface hardness, giving compressive residual stress and etc. However, such mechanical peening process deteriorate surface accuracy due to the severe plastic deformation induced by shot materials.…”

Section: Introductionmentioning

confidence: 99%

Fatigue behavior of A5052 aluminum alloy with diamond-like carbon/electroless nickel plating hybrid coating

Uematsu

Kakiuchi

Adachi

2018

Mechanical Engineering Letters

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Electroless nickel plating was formed on A5052 aluminum alloy, and subsequently diamond-like carbon (DLC) was deposited on nickel plating to fabricate DLC/nickel plating hybrid coating. Cantilever rotating bending fatigue tests were conducted using the specimens with and without coatings. The fatigue strengths of the specimens with DLC or nickel plating single layers were higher than those of the substrate without coating. However, the specimens with nickel plating had large scatter in the fatigue strengths due to some cracking in the coatings. When DLC was deposited on the nickel-plating layer, the fatigue strengths were further improved compared with the specimens with DLC or nickel plating single layers. The observation of fatigue fracture surfaces revealed that fatigue crack initiated at the substrate just beneath the coating in the specimens with DLC or nickel plating single layers. However, subsurface fatigue crack initiation occurred in high cycle fatigue regime of the specimen with hybrid coating. It indicated that the improvement of fatigue strengths could be attributed to the suppression of fatigue crack initiation by coatings, where hybrid coating was more efficient than DLC or nickel plating single layers.

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Fatigue strength improvement of an aluminum alloy with a crack-like surface defect using shot peening and cavitation peening

Cited by 70 publications

References 24 publications

Effects of laser peening on the fatigue strength and defect tolerance of aluminum alloy

Effects of laser peening on the fatigue strength and defect tolerance of aluminum alloy

Enhancing the high cycle fatigue life of high strength aluminum alloys for aerospace applications

Fatigue behavior of A5052 aluminum alloy with diamond-like carbon/electroless nickel plating hybrid coating

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