Experimental and theoretical studies of corrosion-induced mechanical properties degradation of aircraft 2024 aluminum alloy

In the present work, the influence of the corrosion exposure time on the mechanical properties degradation of the aluminum 2024-T3 alloy is studied. Tensile and fracture toughness mechanical tests had been carried out on pre-corroded specimens, exposed for different times to laboratory accelerated, exfoliation corrosion solution. The test results show that both the tensile mechanical properties as well as the fracture toughness exponentially decreased with increasing exposure time. A mechanical model has been devised to calculate the specimen’s remaining effective thickness after different corrosion exposure times. It has been shown that the decrease in the alloy’s fracture toughness is mainly associated with the thickness reduction degradation mechanism and a small reduction is attributed to hydrogen embrittlement. The hydrogen embrittlement degradation mechanism is saturated for exposure times up to 24 h. For higher exposure times, the prevailing degradation mechanism of alloy’s fracture toughness is the formation of corrosion-induced surface cracks and the resulting reduction of the effective thickness of the test specimen. An FE model has been developed for a fast calculation of the uncorroded alloy’s fracture toughness with good results. The model has also been exploited to predict the alloy’s fracture toughness degradation for the increasing exposure time to corrosive environment.