Fatigue Behaviour of Thin Coated Al 7075 Alloy with Low Temperature PVD Coatings

7075-T6 is one of the most performing aluminium alloys, considering its mechanical properties and good fatigue behaviour. In this work the influence of WC/C and DLC PVD coatings on the fatigue behaviour was investigated by rotating bending tests at 2·105cycles. The fatigue behaviour of polished and untreated specimens was considered as reference. In order to decouple the effect of the deposition temperature from the coating one, some uncoated specimens were submitted to the thermal cycles of the WC/C and DLC processes and then tested under fatigue loading. Fatigue life was determined using a step-loading technique. SEM micrographs of the fracture surfaces were taken in order to characterize the fatigue mechanisms of coated and uncoated specimens.

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Fatigue Behaviour of DLC Coated Al 7075-T6 Alloy in an Aggressive Mixture

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.627.81 ◽

2014 ◽

Vol 627 ◽

pp. 81-84 ◽

Cited By ~ 7

Author(s):

Sergio Baragetti ◽

Riccardo Gerosa ◽

Francesco Villa

Keyword(s):

High Performance ◽

Contact Fatigue ◽

Fatigue Behaviour ◽

Fatigue Tests ◽

Structural Elements ◽

Pvd Coatings ◽

Bending Fatigue ◽

Al 7075 ◽

Rotating Bending Fatigue ◽

Rotating Bending

7075-T6 aluminium alloy is commonly adopted in high performance structures and components. Its fatigue behaviour is however dramatically worsened by exposure to aggressive environments. The deposition of PVD coatings, which are commonly adopted to increase the surface properties of structural elements in terms of hardness, contact fatigue and wear resistance, could be beneficial also for the fatigue behaviour of a 7075-T6 substrate in an aggressive environment. In the present work, Diamond Like Carbon (DLC) PVD coated 7075-T6 specimens immersed in methanol have been analysed, by means of step-loading rotating bending fatigue tests (R = -1) at 2·105 cycles. Coated specimens were tested in laboratory air for comparison, and uncoated polished samples were studied in both the environments to obtain reference values. SEM micrographs of the fracture surfaces were taken to investigate the effects of the corrosive environment on the failure mechanism.

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Study of the Effect of DCT and PVD Treatments on the Fatigue Behaviour of AISI 302 Stainless Steel

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.417-418.49 ◽

2009 ◽

Vol 417-418 ◽

pp. 49-52 ◽

Cited By ~ 2

Author(s):

Paolo Baldissera ◽

Stefano Cavalleri ◽

Paolo Marcassoli ◽

Federico Tordini

Keyword(s):

Stainless Steel ◽

Vapor Deposition ◽

Physical Vapor Deposition ◽

Cryogenic Treatment ◽

Fatigue Behaviour ◽

Combined Effects ◽

Deep Cryogenic Treatment ◽

Bending Tests ◽

Standard Specimens ◽

Rotating Bending

In this paper the influence of DCT (Deep Cryogenic Treatment) and a CrN arc-deposited PVD (Physical Vapor Deposition) coating on the fatigue behaviour of AISI 302 stainless steel was studied. Rotating bending tests were carried out on standard specimens to evaluate the fatigue limit at 300000 load cycles. The single and the combined effects of the two treatments were investigated by addressing untreated, PVD-coated and both PVD-coated and DC-treated specimens to the tests. All the series of specimens were also tested statically and laboratory analyses including fracture surface SEM observations and hardness measurements were performed.

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Comparative Study on the Fatigue Behaviour of SCC and VC

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.627.333 ◽

2014 ◽

Vol 627 ◽

pp. 333-336 ◽

Cited By ~ 3

Author(s):

Sara Korte ◽

Veerle Boel ◽

Wouter de Corte ◽

Geert de Schutter

Keyword(s):

Crack Width ◽

Static Load ◽

Fatigue Loading ◽

Fatigue Behaviour ◽

Self Compacting Concrete ◽

Irreversible Damage ◽

Bending Tests ◽

Loading Rates ◽

Four Point Bending ◽

Concrete Type

Continuous cyclic loading on concrete constructions involves a progressive cracking mechanism, leading to significant changes of the material properties during the lifetime of the structure. Gradually, irreversible damage is inflicted and the carrying capacity is affected, which may cause structural collapse at a stress or strain level much lower than in case of a single static load. This so-called fatigue phenomenon is well-documented in literature for traditional, vibrated concrete (VC), but this is not the case for self-compacting concrete (SCC). Given the fact that this latter concrete type is already used worldwide in many types of structures, including cyclically loaded ones, a good knowledge and understanding of the static and fatigue material behaviour is crucial. Up till now, it is unsure whether SCC performs better, worse, or equally under fatigue loading conditions. Therefore, in this study, destructive four-point bending tests are performed on large beams, made from VC and SCC, both statically and cyclically (at different loading rates). A comparison of the deflection, strain, crack pattern and crack width evolution of the different concrete types is made. The results reveal some significant differences regarding concrete strain and crack width development during the cyclic tests.

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Fatigue Behaviour of Notched PVD-Coated Titanium Components

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.348-349.313 ◽

2007 ◽

Vol 348-349 ◽

pp. 313-316 ◽

Cited By ~ 5

Author(s):

Sergio Baragetti ◽

Luca Lusvarghi ◽

F. Pighetti Mantini ◽

Federico Tordini

Keyword(s):

Titanium Alloy ◽

Fatigue Limit ◽

Fatigue Behaviour ◽

Bending Tests ◽

Cross Section Area ◽

Section Area ◽

Minimum Cross Section ◽

Surface Notch ◽

Rotating Bending ◽

Pvd Film

In this paper the fatigue behaviour of Ti-6Al-4V alloy coated with a TiN arc-deposited PVD film was studied. Rotating bending tests (R = -1) were carried out on standard “hourglass” specimens to evaluate the fatigue limit at 200000 load cycles. Conventional and notched (120° Vnotch transversal to the rotating axis at the minimum cross section area) specimens were tested, both coated and uncoated, to investigate the effect of the coating on the fatigue limit of the titanium alloy, with and without the surface notch. Fracture surfaces were observed by SEM. The coating did not improve the titanium alloy fatigue life.

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Fatigue behaviour and crack growth rate of cryorolled Al 7075 alloy

Materials Science and Engineering A ◽

10.1016/j.msea.2011.05.021 ◽

2011 ◽

Vol 528 (24) ◽

pp. 7124-7132 ◽

Cited By ~ 29

Author(s):

Prosenjit Das ◽

R. Jayaganthan ◽

T. Chowdhury ◽

I.V. Singh

Keyword(s):

Growth Rate ◽

Crack Growth Rate ◽

Crack Growth ◽

Fatigue Behaviour ◽

Al 7075 ◽

7075 Alloy

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Effect of loading-program modifications in rotating-bending tests on fatigue behaviour of aircraft material specimens

Materialwissenschaft und Werkstofftechnik ◽

10.1002/mawe.19790100907 ◽

1979 ◽

Vol 10 (9) ◽

pp. 303-312 ◽

Cited By ~ 1

Author(s):

A. Buch

Keyword(s):

Fatigue Behaviour ◽

Bending Tests ◽

Aircraft Material ◽

Rotating Bending

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Theoretical and Experimental Fatigue Strength Calculations of Lips Compensating Circumferential Backlash in Gear Pumps

Energies ◽

10.3390/en14010251 ◽

2021 ◽

Vol 14 (1) ◽

pp. 251

Author(s):

Piotr Osiński ◽

Grzegorz Chruścielski ◽

Leszek Korusiewicz

Keyword(s):

Maximum Stress ◽

Theoretical Calculations ◽

Fatigue Loading ◽

Minimum Thickness ◽

Bending Tests ◽

External Gear Pumps ◽

Gear Pumps ◽

In Series ◽

Number Of Cycles ◽

Technical Solutions

This article presents theoretical and experimental calculations of the minimum thickness of a compensation lip used in external gear pumps. Pumps of this type are innovative technical solutions in which circumferential backlash (clearance) compensation is used to improve their volumetric and overall efficiency. However, constructing a prototype of such a pump requires long-lasting research, and the compensation lip is its key object, due to the fact that it is an element influenced by a notch and that it operates in unfavorable conditions of strong fatigue stresses. The theoretical calculations presented in this article are based on identifying maximum stress values in a fatigue cycle and on implementing the stress failure condition and the conditions related to the required value of the fatigue safety factor. The experimental research focuses on static bending tests of the lips as well as on the fatigue loading of the lips in series of tests at increasing stress values until lip failure due to fatigue. The tests allowed the minimum lip thickness to be found for the assumed number of fatigue cycles, which is 2.5 times the number of cycles used in wear margin tests.

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