Effect of microarc oxidised layer thickness on plain fatigue and fretting fatigue behaviour of Al-Mg-Si alloy

• The objective of this work was to investigate the performance of microarc oxide coatings of two different thicknesses (40 and 100 mu m) on Al-Mg-Si alloy samples under plain fatigue and fretting Fatigue loadings. Tensile residual stress present in the substrate of 40 mu m thick coated samples induced early crack initiation in the substrate and so their plain fatigue lives were shorter than those of untreated specimens. Presence of more pores and tensile surface residual stress in 100 mu m thick coated samples caused early crack initiation at the surface leading to their inferior plain fatigue lives compared with 40 mu m thick coated samples. While the differences between the lives of coated and uncoated specimens were significant under plain fatigue loading, this was not the case under fretting fatigue loading. This may be attributed to relatively higher surface hardness of coated specimens. The performance of 40 mu m thick coated samples was better than that of 100 mu m thick coated specimens under both plain fatigue and fretting fatigue loadings. (C) 2007 Elsevier Ltd. All rights reserved.

Nyckelord

fretting fatigue

microarc oxidation

residual stress

friction force

Al-Mg-Si alloy

PLASMA ELECTROLYTIC OXIDATION

ALUMINUM-ALLOY

MECHANICAL-PROPERTIES

TI-6AL-4V ALLOY

OXIDE COATINGS

Engineering

Mechanical

Materials Science

Multidisciplinary

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