Corrosion fatigue behavior of a Mg-9Gd alloy under different glucose concentrations

Under physiological conditions, Mg alloy bone implants are subjected to mechanical stress and corrosion. Consequently, developing practical clinical applications, understanding the corrosion fatigue (CF) behavior of Mg alloy is crucial. The Mg alloys is presented with a new challenge by the rising prevalence of metabolic disorders such as diabetes, as the high-glucose environment can adversely affect their behavior. This study investigates the CF behavior of the Mg-9Gd-2Nd-0.5Zr-0.5In alloy (designated as Mg-9Gd) in a simulated high-glucose environment, with particular emphasis on the influence of glucose concentrations (1 g/L and 3 g/L) on its CF lifespan. To elucidate the underlying degradation mechanisms, complementary static corrosion tests were performed. The results show that the synergistic effect of cyclic loading and corrosive media substantially accelerates CF failure, particularly at higher glucose concentrations. Fractographic analysis reveals that fatigue cracks initiate at surface pits caused by localized corrosion and propagate in a brittle manner. Additionally, the static corrosion tests reveal that the oxidation of glucose combined with Cl − destabilizes the corrosion product layer on the alloy surface, further intensifying localized corrosion. This disruption enhances pitting, which facilitates crack initiation and reduces fatigue life.