A fracture-mechanical model for the prediction of the corrosion dependent local fracture toughness of aluminium alloy 2024

Abstract

Extensive experimental investigations have shown that the exposure of aluminium alloy 2024 specimens to an exfoliation corrosion environment leads to a dramatic reduction in the tensile ductility, which is due to hydrogen embrittlement. In the present work, the corrosion-induced reduction in the tensile ductility of the aluminium alloy 2024 is correlated to the reduction in fracture toughness. A location- and time-dependent quantity referred to as local fracture toughness is introduced. A multiscaling approach is implemented to relate tensile properties degradation due to exfoliation corrosion to local material properties in the vicinity of the crack tip. For the prediction of the local fracture toughness value of the corroded material ahead of the crack tip, a fracture-mechanical model has been developed by utilizing the multiscaling approach. The predicted local fracture toughness values have been exploited to estimate the experimentally observed embrittlement of panels exposed to exfoliation corrosion.

Keywords

aluminium alloy corrosion hydrogen embrittlement local fracture toughness

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