The biodegradable nature of magnesium in aqueous mediums makes it an attractive material for various biomedical applications when it is not recommended that the material stay permanently in the body. Some of the main challenges that hinder the use of magnesium for bone fracture repair are its limited mechanical strength and fast corrosion rates. To this end, we developed a novel Mg-Zn-Ca-Mn-based alloy and post-fabrication methods that can deliver high-strength and corrosion-controlled implant materials to address these challenges. This study is focused on assessing the in vitro corrosion and in vivo biocompatibility of the developed magnesium-based alloy and post-fabrication processes. The developed heat treatment process resulted in an increase in the microhardness from 71.9 ± 5.4 HV for the as-cast Mg alloy to as high as 98.1 ± 6.5 HV for the heat-treated Mg alloy, and the ceramic coating resulted in a significant reduction in the corrosion rate from 10.37 mm/yr for the uncoated alloy to 0.03 mm/yr after coating. The in vivo assessments showed positive levels of biocompatibility in terms of degradation rates and integration of the implants in a rabbit model. In the rabbit studies, the implants became integrated into the bone defect and showed minimal evidence of an immune response. The results of this study show that it is possible to produce biocompatible Mg-based implants with stronger and more corrosion-controlled properties based on the developed Mg-Zn-Ca-Mn-based alloy and post-fabrication methods.

This study examines the effects of heat treatment on corrosion behavior of equiatomic AlCoCrNiFe high-entropy alloy within a solution treatment temperature range of 800–1100 °C. Experimental observations on phase formation were compared with thermodynamic predictions. The microstructure, mechanical properties, and aqueous corrosion behavior of the as-deposited alloy were analyzed and contrasted with heat-treated samples. The results showed a decline in the corrosion resistance of the AlCoCrNiFe after heat treatment, which was attributed to chemical segregation and Cr depletion in the microstructure matrix. Additionally, post-corrosion analysis revealed a reduced volume fraction of protective oxides in the heat-treated samples.