Study of Microscopic Residual Stresses in an Extruded Aluminium Alloy Sample after Thermal Treatment

Aluminium alloys have very useful properties. Because they are light, easily formed, machined and cast, they are widely used in aircraft industry and automotive industry. Their mechanical properties are mostly influenced by former mechanical and thermal treatment. An extruded aluminium alloy EN AW – 2007 was used in the as-received state and the specimens were thermally cycled with increasing the upper temperature step-by-step. After each thermal cycle the stress-amplitude dependence of internal friction was measured at room temperature. The quality factor Q-1was measured by a resonant method at a frequency of 20 kHz. Thermal and mechanical treatments influenced the anelastic properties of the material. The thermal treatment affects the internal friction in a positive way, while the mechanical treatment decreases Q-1. The microstructural changes were observed by optical microscopy.

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Dilatometry Behavior of Extruded Aluminium Alloy Reinforced with Carbides

Materials Development and Processing - Bulk Amorphous Materials, Undercooling and Powder Metallurgy ◽

10.1002/3527607277.ch50 ◽

2006 ◽

pp. 308-314

Author(s):

L. E. G. Cambronero ◽

E. M. Ruiz-Navas ◽

J. M. Ruiz-Román ◽

J. M. Ruiz-Prieto

Keyword(s):

Aluminium Alloy ◽

Extruded Aluminium Alloy

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Surface Modification Analysis after Shot Peening of AA 7075 in Different States

Materials Science Forum ◽

10.4028/www.scientific.net/msf.768-769.519 ◽

2013 ◽

Vol 768-769 ◽

pp. 519-525 ◽

Cited By ~ 1

Author(s):

Sebastjan Žagar ◽

Janez Grum

Keyword(s):

Residual Stress ◽

Surface Layer ◽

Residual Stresses ◽

Aluminium Alloy ◽

Shot Peening ◽

Fatigue Testing ◽

Stress Profile ◽

Treatment Conditions ◽

Stress Profiles ◽

Compressive Residual Stresses

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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Experimental Evaluation of Residual Stresses in the Aluminium Alloy AA 6082 by Use of the Satoh Test

Materials for Transportation Technology ◽

10.1002/3527606025.ch20 ◽

2005 ◽

pp. 116-123

Author(s):

Ragnhild Aune ◽

Øyvind Gundersen

Keyword(s):

Residual Stresses ◽

Aluminium Alloy ◽

Experimental Evaluation

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Effects of Hard Surface Grinding and Activation on Electroless-Nickel Plating on Cast Aluminium Alloy Substrates

Journal of Coatings ◽

10.1155/2014/841619 ◽

2014 ◽

Vol 2014 ◽

pp. 1-10 ◽

Cited By ~ 6

Author(s):

Olawale Olarewaju Ajibola ◽

Daniel T. Oloruntoba ◽

Benjamin O. Adewuyi

Keyword(s):

Aluminium Alloy ◽

Electroless Nickel ◽

Sodium Hypophosphite ◽

Palladium Chloride ◽

Alloy Sample ◽

Sand Cast ◽

Hard Surface ◽

Cast Aluminium ◽

Surface Polishing ◽

Cylinder Piston

This work examined effects of hard surface polishing grits and activation on electroless-nickel (EN) plating on cast aluminium alloy substrates in sodium hypophosphite baths. As-received aluminium alloy sample sourced from automobile hydraulic brake master cylinder piston was melted in electric furnace and sand cast into rod. The cast samples were polished using different grits (60 μm–1200 μm) before plating. The effects on adhesion, appearance, and quantity of EN deposits on substrates were studied. Observation shows that the quantity of EN deposit is partly dependent on the alloy type and roughness of the surface of the substrates, whereas the adhesion and brightness are not solely controlled by the degree of surface polishing. The best yield in terms of adhesion and appearance was obtained from the activation in zincate and palladium chloride solutions. Higher plating rates (g/mm2/min) of 3.01E-05, 2.41E-05, and 2.90E-05 were obtained from chromate, zincate, and chloride than 8.49E-06, 8.86E-06, and 1.69E-05 as obtained from HCl etched, NaOH, and H2O activated surfaces, respectively.

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