In vitro bio-corrosion behaviors of biodegradable AZ31B magnesium alloy under static stresses of different forms and magnitudes

Biomedical degradable materials would be subjected to different degrees and forms of static stress after being implanted in the human body. In this work, the biocorrosion behaviors of AZ31B magnesium alloy under different stress forms with different magnitudes (20 ∼ 150 MPa) were studied. It was found that the corrosion behaviors at stressed conditions were severer than those at unstressed conditions and corrosion rates were obviously accelerated. The biocorrosion behaviors are more sensitive to the effects of tensile loads than to compressive loads. A biocorrosion numerical model on the degradation process of Mg alloy under static loads was established. The corrosion current density (icorr) of Mg alloy and the applied static stress (σ) matches a linear relationship of ln icorr ∼ σ well during the early stage (within 24 hrs) while deviated gradually in the latter period of corrosion. This work could provide a guidance and theoretical reference for further researches on the biocorrosion behaviors and practical clinical applications of the biomedical materials subjected to physiological loads.