Effect of Alternate Corrosion and Fatigue on Fatigue Crack Growth Characterization of 2024-T4 Aluminum Alloy

Abstract

To investigate the effect of alternate corrosion and fatigue on fatigue crack growth characterization of 2024-T4 aluminum alloy, the pure fatigue test, “corrosion + fatigue” test (commonly known as pre-corrosion fatigue), and the “fatigue + corrosion + fatigue” alternating test of single-sided notched specimen of 2024-T4 aluminum alloy were carried out. The fatigue crack life of alternate corrosion and fatigue is longer than that of the pre-corrosion fatigue when the corrosion time is the same. And the more the times of alternating, the longer the crack growth life will be. This is mainly because the fatigue crack growth rate will change suddenly, which will have a certain hysteresis effect on the fatigue crack growth. The corrosion and fracture morphology characteristics of the alternate test were examined by scanning electron microscopy (SEM), and the composition of corrosion products was examined by the energy dispersion spectrum (EDS). The prediction model of fatigue crack growth rate considering the alternating hysteresis effect of corrosion and fatigue based on the Paris formula was established, and the parameters and precision of the model were calculated and verified. The results show that the model has certain engineering application value.