Investigation on the Mechanical and Corrosion Properties of ZnMnSr Alloys for Biodegradable Orthopedic Implants

Zinc-based alloys with good biocompatibility and corrosion resistance are potential candidates for bioabsorbable implants. Herein, a series of Zn99-x Mn x Sr1 (x = 0.2, 0.3, 0.5, and 0.9 wt%) alloys are investigated using single-channel vertical extrusion (SCVE) and equal-channel angular pressing (ECAP) procedures, respectively. It is found that the amount of Mn significantly affects the mechanical properties of alloys. For example, the yield strength, tensile strength, and elongation of Zn-1Sr alloys can reach up to 204.73 +/- 3.6 MPa, 244.04 +/- 6.45 MPa, and 47.1 +/- 3% with 0.99 wt% Mn addition after the SCVE process, which can meet the requirement of orthopedic implant applications. Moreover, the mechanical properties of current alloys are reduced with the combined SCVE + ECAP process, which may be due to more aggregation with the secondary phase within the matrix hcp(Zn). Furthermore, the polarization curves and immersion tests show that the corrosion rate is accelerated for the alloys processed with the combined SCVE + ECAP process (0.34-0.171 mm/y) compared with the ones processed only with SCVE (0.011-0.032 mm/y). The present finds provide a contribution for biodegradable Zn-based alloys development.