Effect of Hydrogen on Mechanical Degradation and Fatigue in 7075 Aluminium Alloy with In-situ Hydrogenation

The present study investigated the effect of hydrogen on the mechanical degradation and the fatigue crack growth rate of 7075 T6 Aluminium alloy by in-situ cathodic hydrogen charging. The effect of strain rates on tensile deformation in air and by in-situ hydrogen charging was studied. The fatigue crack growth tests were carried out at constant stress intensity factor ranges (ΔKs). The effects of different parameters, like stress intensity factor range (ΔK), stress ratio (R), and frequency have been investigated. The fatigue crack growth rate was found to increase in hydrogenating environment compared to the crack growth ratein air at different stress ratios. The effect of hydrogen on the fatigue crack growth rate was more at lower ΔK in comparison to higher ΔK. Fracture surfaces and crack morphologies were studied using scanning electron microscopy analysis.