Transverse fatigue behaviour and residual stress analyses of double sided FSW aluminium alloy joints

The paper deals with the effect of different shot peening (SP) treatment conditions on the ENAW 7075-T651 aluminium alloy. Suitable residual stress profile increases the applicability and life cycle of mechanical parts, treated by shot peening. The objective of the research was to establish the optimal parameters of the shot peening treatment of the aluminium alloy in different precipitation hardened states with regard to residual stress profiles in dynamic loading. Main deformations and main residual stresses were calculated on the basis of electrical resistance. The resulting residual stress profiles reveal that stresses throughout the thin surface layer of all shot peened specimens are of compressive nature. The differences can be observed in the depth of shot peening and the profile of compressive residual stresses. Under all treatment conditions, the obtained maximum value of compressive residual stress ranges between -200 MPa and -300 MPa at a depth between 250 μm and 300 μm. Comparison of different temperature-hardened aluminium alloys shows that changes in the Almen intensity values have greater effect than coverage in the depth and profile of compressive residual stresses. Positive stress ratio of R=0.1 was selected. Wöhler curves were determined in the areas of maximum bending loads between 30 - 65 % of material's tensile strength, measured at thinner cross-sections of individual specimens. The results of material fatigue testing differ from the level of shot peening on the surface layer.

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Untersuchungen zum Ermüdungsverhalten der Aluminiumlegierung AA 6013 T6 in korrosivem Medium / An Investigation of the Fatigue Behaviour of the Aluminium Alloy AA 6013 T6 in a Corrosive Medium...

Practical Metallography ◽

10.1515/pm-2001-380302 ◽

2001 ◽

Vol 38 (3) ◽

pp. 119-137

Author(s):

I. Haase ◽

K. Nocke ◽

H. Worch ◽

G. Zouhar ◽

G. Tempus

Keyword(s):

Aluminium Alloy ◽

Corrosive Medium ◽

Fatigue Behaviour

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Fatigue Failure Modes in Self-Piercing Riveted Aluminium Alloy Joints

Volume 3 ◽

10.1115/esda2004-58320 ◽

2004 ◽

Author(s):

L. Han ◽

K. Young ◽

R. Hewitt ◽

A. Chrysanthou ◽

J. M. O’Sullivan

Keyword(s):

Aluminium Alloy ◽

Fatigue Failure ◽

Failure Modes ◽

Surface Condition ◽

Fatigue Behaviour ◽

Alloy Sheet ◽

Static Tests ◽

Failure Patterns ◽

Interfacial Conditions ◽

Sheet Surface

Self-piercing riveting, as an alternative joining method to spot-welding, has attracted considerable interest from the automotive industry and has been widely used in aluminium intensive vehicles. One of the important factors that need to be considered is the effect of cyclic loading in service, leading to possible fatigue failure. The previous work reported in the public domain on the behaviour of self-piercing rivets has mainly focused on static tests. The work which is reported in this paper is concerned with the fatigue behaviour of single-rivet joints, joining two 2mm 5754 aluminium alloy sheets. The investigation also examined the effect of interfacial conditions on the fatigue behaviour. A number of fatigue failure mechanisms were observed based on rivet fracture, sheet fracture and combinations of these. The investigation has shown that they were dependent on the applied load and the sheet surface condition. Three-parameter Weibull analysis, using Reliasoft Weibull ++5.0 software, was conducted to analyse the experimental results. The analysis enabled the prediction of early-type failure (infant mortality failure) and wear-out failure patterns depending on the condition of the self-piercing riveted joints and the alloy sheet surface.

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Effect of 7050 Aluminium Alloy Microstructure on Residual Stress by Laser Shock Processing

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.463-464.1363 ◽

2012 ◽

Vol 463-464 ◽

pp. 1363-1367

Author(s):

M.L. Zhang ◽

J.M. Wang ◽

Y.F. Jiang ◽

Q.L. Zhang ◽

Q.L. Zhou

Keyword(s):

Residual Stress ◽

Aluminium Alloy ◽

Compressive Stress ◽

Solution Treatment ◽

Aging Treatment ◽

Residual Compressive Stress ◽

Original Structure ◽

Laser Shock ◽

Laser Shock Processing ◽

Shock Processing

The solution treatment and solution and aging treatment (T6) were disposed on 7050 aluminium alloy, then local processed by laser shock processing (LSP) with high-rate neodymium glass laser. The microhardness and residual stress on the surface of 7050 aluminium alloy were tested, then how the microstructure influences the residual stress on the surface of 7050 aluminium alloy by laser shock processing was analysed. The results show that the microhardness and residual compressive stress on the surface of 7050 aluminium alloy treated by solution and aging treatment was higher, and decreased obviously treated by solution treatment; the microhardness and residual compressive stress on the surface of 7050 aluminium alloy increased obviously by solution treatment and solution and aging treatment after laser shock processing; treated by solution treatment and solution and aging treatment, the microhardness and residual compressive stress of the material with uniform original structure was higher than the material with nonuniform original structure.

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