Zinc based bioalloys processed by severe plastic deformation – A review

Zinc based alloys have recently attracted great attention as promising biodegradable metals. Zinc exhibits moderate degradation rates in biological fluid and the zinc releases during the degradation process is considered safe to human systems. However, these materials exhibit critical limitations in terms of mechanical properties for medical applications. Adding alloying elements as well as grain refinement by thermomechanical processing are considered as effective techniques to address this problem. Severe plastic deformation (SPD) methods were considered in recent few years to process the zinc-based bioalloys to achieve acceptable mechanical characteristic while retaining their desired biocorrosion behavior. Summarizing present literature implied that Mg, Ag, Mn, and Ca containing zinc bioalloys may provide an improved strength and ductility approaching the common mechanical criteria. However, due to low melting temperature of zinc, there remains new uncertainties in mechanical response as future challenge, including low creep resistance and high susceptibility to natural aging at body temperature.