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Abstract

Aluminium–copper alloys AA2219 and AA2024 are commonly anodised. The fatigue strength declined by 41 and 29%, respectively, following sulphuric acid anodisation of large cross-section material. The fatigue strength loss was significantly less (3 and 12%, respectively) for sulphuric acid anodised small cross-section material. For large cross-section material, fatigue fractures originated at pits formed from Cu rich constituent dissolution during anodising. No pitting and less fatigue strength loss were observed for small cross-section material compared with large cross-section material. The microstructure of large cross-section material containing a network of Cu rich constituent particles compared with small cross-section material where the particles are small and disconnected relates to the extent of working during mill processing. Limited data on chromic acid anodised material is given.

Keywords

ANODISATION FATIGUE ALUMINIUM ALLOYS COPPER CORROSION

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Relationship of microstructure to fatigue strength loss in anodised aluminium–copper alloys

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