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Abstract:
Micro-arc oxidation(MAO) coatings with different thickness (10 μm, 15 μm and 20 μm) were deposited on LD10 Al alloy samples using MAO processing. The samples were tested using a rotating bending fatigue tester to character their fatigue properties. Scanning electron microscopy (SEM) was used to observe the microstructure and fatigue fracture morphology of the specimen with MAO coatings. X-ray diffraction (XRD) was employed to analyze the phases and residual stress in the coatings. The results show that the MAO coating is mainly composed of AlSi0.5O2.5 amorphous phase, and the net micro-cracks observed in the coating initiate in the discharge channel and end at the region near the discharge channel. The tensile residual stress presented at the interface of the substrate and the coating induces early crack initiation and propagation. Compared to the sample without MAO coating, the reduction of fatigue life are 63%, 75% and 65%, and the reduction of fatigue limit are 9.5%, 7.9% and 9.9% for the samples with the MAO coatings thickness of 10μm, 15μm and 20μm, respectively.
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Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment
ISSN: 1009-6264
Year: 2010
Issue: 2
Volume: 31
Page: 123-127
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