Effects of heat treatment on the corrosion behavior and mechanical properties of biodegradable Mg alloys

Biodegradable magnesium (Mg) alloys exhibit great potential for use as temporary structures in tissue engineering applications. Such degradable implants require no secondary surgery for their removal. In addition, their comparable mechanical properties with the human bone, together with excellent biocompatibility, make them a suitable candidate for fracture treatments. Nevertheless, some challenges remain. Fast degradation of the Mg-based alloys in physiological environments leads to a loss of the mechanical support that is needed for complete tissue healing and also to the accumulation of hydrogen gas bubbles at the interface of the implant and tissue. Among different methods used to improve the performance of the biodegradable Mg alloys to address these challenges, it appears that heat treatment is the most effective way to modify the microstructure and thus the corrosion behavior and mechanical properties without changing the composition or shape of the alloys. A desirable combination of corrosion and mechanical properties can be obtained through a precise control of the heat treatment parameters. In this report, the effects of different heat treatments (T4 and T6) on the microstructure, corrosion behavior, and mechanical properties of some of the most important heat-treatable biodegradable Mg alloys (Mg-Zn, Mg-Gd, Mg-Y, Mg-Nd, Mg-Al and Mg-Ag) are examined as well as new perspectives to enhance their clinical implementation.