Corrosion fatigue of the extruded Mg–Zn–Y–Nd alloy in simulated body fluid

Magnesium alloys were considered to be used as biodegradable implants due to their biocompatibility, biodegradability and nontoxicity. However, under the simultaneous action of corrosive environment and mechanical loading in human body, magnesium alloys are easy to be affected by corrosion fatigue and stress corrosion cracking. In this work, the fatigue behavior of the extruded Mg–Zn–Y–Nd alloy used for vascular stents was studied both in air and in simulated body fluid (SBF). It was revealed that the fatigue limit of as-extruded Mg–Zn–Y–Nd alloy in air is about 65 MPa at 107 cycles, while there is no limit in SBF and shows a linear relationship between the fatigue life and stress amplitudes. The fatigue crack source in air was formed by the inclusions and defects. However, the stress corrosion and hydrogen embrittlement are the main reasons for the formation of the fatigue initial crack source in SBF. Keywords: Biodegradable magnesium alloy, Corrosion fatigue, Simulated body fluid, Fatigue crack source