Residual stress gradient and relaxation upon fatigue deformation of diamond-like carbon coated aluminum alloy in air and methanol environments

Srinivasan, Nedunchezhian; Bhaskar, Lalith Kumar; Kumar, Ravi; Baragetti, Sergio

doi:10.1016/j.matdes.2018.09.022

Cited by 29 publications

(16 citation statements)

References 34 publications

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“…The fatigue strength obtained for the uncoated samples subjected to the thermal treatment and the fatigue strength of the samples with a DLC surface layer were very similar. Furthermore, the small thermal load applied during the film deposition, combined with the favorable residual compressive stress state induced by the deposition of the film, 7,30,34 might be responsible for the reduced slope of the normalσnormalmax−normalNnormalcycles curve for the samples with the DLC film between 2⋅105 and 107 cycles. At approximately 107 cycles it seems that the fatigue strength of untreated and treated specimens is similar.…”

Section: Resultsmentioning

confidence: 99%

“…37 The maximum temperature reached during the production of the DLC film on the specimens was 180 °C in order to avoid a strong reduction in the mechanical properties of the material (the annealing temperature of the aluminum alloy considered is 415 °C, its solution temperature is between 466 and 482 °C, and its ageing temperature is equal to 121 °C 36 ) As demonstrated, 30 film deposition does not induce crystallographic changes in the aluminum alloy substrate. The scanning electron micrograph performed in a previous study 30 revealed the actual morphology of the film, consisting of a bi-layer architecture that improves adhesion properties: the layer close to the substrate is 1 μm thick, columnar due to the growth phenomenon in the early stages of the deposition process, and consists of 55.2 wt.% C, 31.2 wt.% W, 0.75% wt.% Ti, 2.8% wt.% Cr and 10.0% Al; the second layer is 1 μm thick and consists of 81.9 wt.% C, 15.6 wt.% W, 0.5 wt.% Cr and 2.0 wt.% Al. Small hillocks induced by the deposition process were observed on the upper surface of the film.…”

Section: Methodsmentioning

confidence: 99%

“…The film produced is very hard and stiff and undergoes significant elastic recovery compared to 7075 substrate, as shown in Table 2, which reports the results of the nano-indentations tests performed with an applied load of 4 mN. 30 A Talysurf profilometer measured the roughness of the surface. An average roughness of R a ¼ 0.034 mm and R a ¼ 0.045 mm was measured on the specimens before and after the film deposition, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…15,16,23 DLC films can present flaws that lead to corrosion of the specimen/component 24 and multilayer architecture is therefore preferable. 25 Furthermore, deposition of DLC films reduces the tribocorrosion of alloys in harsh water-containing environments [26][27][28][29] and induces high compressive residual stresses 30 which can be responsible for an increment in the strength of the material under cyclic loading. The residual stress field is due to the coefficient of thermal expansion mismatch and structural misfit between the coating and the substrate.…”

Section: Introductionmentioning

confidence: 99%

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Effects of thin hard film deposition on fatigue strength of AA7075-T6

Baragetti

Arcieri

2020

Proceedings of the Institution of Mechanical Engineers, Part C:

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Thanks to their favorable strength-to-weight ratio, Aluminum-Zinc alloys are often used in high-performance industrial sectors. These alloys are characterized by poor erosion resistance, which could be increased by the deposition of thin films. For example, PVD (Physical Vapor Deposition) films can reduce wear and ensure appreciable performance in aggressive environments. This paper describes the effects of thin hard film deposition on the strength of AA7075 under cyclic loading. Uncoated samples and samples with a DLC (Diamond-Like Carbon) surface layer were tested with a rotating bending fatigue machine within the range of [Formula: see text]–[Formula: see text] cycles. Two regression models were tested to study the relationship between fatigue strength and number of cycles within the range considered. For the samples without the film, even a linear regression can be suitable. With regard to the fatigue strength of the samples with surface layer, a piecewise linear regression is suggested, although a high scatter of experimental data can be observed. Finite element (FE) modelling was used to calculate the stresses induced by bending moment. The bending stresses were added to the residual stresses induced by the film deposition. The maximum value was found beneath the sample surface. Therefore, crack nucleation is expected under the surface of samples with film. The fatigue cracks initiate at the surface in untreated samples.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effects of thin hard film deposition on fatigue strength of AA7075-T6

Baragetti

Arcieri

2020

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…In the view of understanding the methods of coating deposition by using sputtering deposition techniques [113], Ager et al [114] discussed whether the shifting and broadening of the Raman line from film was due to stress. They observed that the diamond Raman line was moved by 2.5 cm −1 to a higher frequency, which could be clarified by stress of 9.0 × 10 8 Pa, which agreed with other measurements in Table 3.…”

Section: Thermal Stress: Dlc Filmsmentioning

confidence: 99%

Diamond-Like Carbon (DLC) Coatings: Classification, Properties, and Applications

et al. 2021

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DLC coatings have attracted an enormous amount of interest for science and engineering applications. DLC occurs in several different kinds of amorphous carbon materials. Owing to the extensive diversity in their properties, DLC coatings find applications in mechanical, civil, aerospace, automobile, biomedical, marine, and several other manufacturing industries. The coating life of DLC is predominately influenced by its constituent elements and manufacturing techniques. Numerous researchers have performed multiple experiments to achieve a robust understanding of DLC coatings and their inherent capabilities to enhance the life of components. In this review, a wide range of DLC coatings and their classification, properties, and applications are presented. Their remarkable performance in various applications has made DLC coatings a promising alternative over traditional solitary-coating approaches.

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One-step method to enhance biotribological properties and biocompatibility of DLC coating by ion beam irradiation

et al. 2022

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A one-step method was developed to create a highly biocompatible micropatterned surface on a diamond-like carbon (DLC) through irradiation with a nitrogen ion beam and thus enhance the biocompatibility of osseointegrated surfaces and biotribological performance of articular surfaces. The biocompatibility and biotribological mechanisms were analyzed in terms of the structure and morphology of DLC. It was demonstrated that a layer enriched in sp3 C−N bonds was formed on the surface of the DLC after nitrogen ion beam irradiation. Moreover, with an increase in the radiation dose, the content of sp3 C−N on the DLC surface increased significantly, and the biocompatibility was positively correlated with it. The adhesion of the MC3T3 osteoblasts increased significantly from 32% to 86% under an irradiation dose of 8 × 1015 ions/cm2. In contrast, the micropattern had a significant negative effect on the adhesion of the osteoblasts as it physically hindered cell expansion and extension. The micropattern with a depth of 37 nm exhibited good friction properties, and the coefficient of friction was reduced by 21% at relatively high speeds.

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Residual stress gradient and relaxation upon fatigue deformation of diamond-like carbon coated aluminum alloy in air and methanol environments

Cited by 29 publications

References 34 publications

Effects of thin hard film deposition on fatigue strength of AA7075-T6

Effects of thin hard film deposition on fatigue strength of AA7075-T6

Diamond-Like Carbon (DLC) Coatings: Classification, Properties, and Applications

One-step method to enhance biotribological properties and biocompatibility of DLC coating by ion beam irradiation

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