Microstructural, Mechanical and Electrochemical Characterization of Calcium Modified Mg-Zn Alloys for Biodegradable Medical Devices

Magnesium has been of interest to researchers as a potential biodegradable alternative to metal orthopedic implants due to its biocompatibility and mechanical properties similar to those of bone. However, magnesium implants corrode more quickly than would be beneficial. This study focused on the influence of calcium modification on the microstructure, mechanical and electrochemical degradation (in simulated body fluids at 25°C and 40°C) of selected Mg-Zn alloys. Four alloys, Mg1Zn, Mg2Zn, Mg1Ca1Zn and Mg1Ca2Zn, were fabricated by levitation induction melting under argon atmosphere. Microstructural characterization was performed using optical microscopy and SEM/EDS analysis, mechanical behavior was evaluated by microhardness testing and Gaussian mixture modeling while corrosion performance was assessed in Ringer lactate solution. The results indicated that calcium addition modified the microstructural morphology. Moderate Ca addition modified the distribution of secondary phases and altered the local mechanical response of the Mg matrix. Among the investigated composition, Mg1Ca1Zn exhibited the best balance between microstructural characteristic, mechanical properties and corrosion resistance These results provide key criteria for the development of future resorbable orthopedic implants that improve patients’ quality of life.