Designing the new microstructure is an effective way to accelerate the biomedical application of magnesium (Mg) alloys. In this study, a novel Mg–8Er–1Zn alloy with profuse nano-spaced basal plane stacking faults (SFs) was prepared by combined processes of direct-chill semi-continuous casting, heat-treatment and hot-extrusion. The formation of SFs made the alloy possess outstanding comprehensive performance as the biodegradable implant material. The ultimate tensile strength (UTS: 318 MPa), tensile yield strength (TYS: 207 MPa) and elongation (21%) of the alloy with SFs were superior to those of most reported degradable Mg-based alloys. This new alloy showed acceptable biotoxicity and degradation rate (0.34 mm/year) and the latter could be further slowed down through optimizing the microstructure. Most amazing of all, the uniquely uniform in vitro/vivo corrosion behavior was obtained due to the formation of SFs. Accordingly we proposed an original corrosion mechanism for the novel Mg alloy with SFs. The present study opens a new horizon for developing new Mg-based biomaterials with highly desirable performances.

In this study, a novel Mg–6Ho–0.5Zn alloy (wt%) containing profuse basal plane stacking faults is prepared with the SFs exhibiting uniform corrosion behaviour, low corrosion rate and high mechanical properties.

Degraded and osteogenic property of coated magnesium alloy was evaluated for the fracture fixation in rabbits. Magnesium alloy AZ31 with a different coating thickness by microarc oxidation was used, and the bilateral radial fracture model was created by the bite bone clamp. Thirty-six New Zealand white rabbits in weight of 2.5~3.0 kg were randomly divided into A, B, and C groups at four time points and other 3 rabbits as the control group without magnesium alloy. Coated magnesium alloy AZ31 was implanted on the fracture and fixed with silk thread. Indexes such as general observation, histology, X-ray, hematology, and mechanical properties were observed and detected at 2nd, 4th, 8th, and 12th week after implantation. Fracture in each rabbit was healed at 12th week after implantation. Among the three groups, the best results of general observation, histology, and X-ray appeared in A group without coating. However, A group showed the worst results from the perspective of mechanical properties about tensile strength and flexural strength, which failed to reach that of the natural bone at the 12th week. Comprehensive results displayed that C group with 20-μm coating was better than others in mechanical properties, while there is no difference between B and C groups in hematology. Degradation rate is inversely proportional to the coating thickness. And magnesium alloy with a 20-μm coating is more suitable for the fracture fixation.