Influence of stamping on the biodegradation behavior of Mg-2Zn-0.5Nd (ZN20) sheet.

Stamping processing is commonly used to form medical devices and implant. However, for biodegradable Mg alloy, the stamping will influence the degradation behavior because of the change in microstructure after stamping. So in this study, the As-rolled Mg-2Zn-0.5Nd alloy (ZN20) was processed by stamping. The microstructure, crystallographic orientation and corrosion performance of this processing method was investigated to reveal the influence of the stamping process on the degradation rate of Rolled Mg-2Zn-Nd (ZN20). The degradation rate was measured by immersion of the Mg-2Zn-0.5Nd alloy in simulated body fluid using Electrochemical Impedance Spectroscopy, Potentiodynamic polarization and mass loss. The in vitro degradation result shows that the degradation rate of the Rolled Mg-2Zn-0.5Nd increased from 0.2 mm/year to 0.5 mm/year after stamping processing. The result reveals that the activation of the tension twin during stamping can remarkably weaken the 0001} basal texture and have a significant influence on the corrosion rate of Stamped Mg-2Zn-0.5Nd sheet. After removing the deformation by annealing, the degradation rate was reduced to 0.15 mm/year. This work is expected to prompt better microstructural design of biomedical Mg in order to control its degradation behavior for biomedical application.