Abstract:Magnesium alloys own excellent biocompatibilities and unique degradation characteristics. However, the poor corrosion resistance in physiological environment seriously restricted its development in clinical applications. In this study, Mg-Zn-Sr-Zr-Mn alloys were prepared by pre-tensile process. XRD (X-ray diffraction), OM (optical microscopy) and SEM (scanning electron microscopy) were used to investigate the relationship between the pre-tensile type variables and the microstructure, corrosion rate and film layer morphology. The results showed that with the increase deformation of pre-stretching, the grain sizes were gradually elongated, the numbers of twins were increased, and the dispersion degrees of precipitated phases were gradually increased. The corrosion rate of the three pre-stretching alloys in electrochemical (0.39→0.25 →0.74mm·y-1) and weight-loss (2.85→1.83→5.88mm·y-1) were both decreased firstly and then increased. Therein, the 4% pre-stretching alloy has high corrosion resistance, which indicated that appropriate pre-tensile deformation could improve the continuity of the precipitated phase at the interface, hinder the corrosion process, and play a positive role in the corrosion properties of the alloys. However, when the pre-tensile deformation continues to increase, a large number of dislocations will be generated and hydrogen diffusion path will be created, which was conducive to hydrogen enrichment and leads to the decrease of corrosion resistance. Moreover, appropriate pre-tensile deformation could improve the corrosion uniformity, densification and continuity of the film-layer, and delay the corrosion process by changing the redistribution of residual-stress.