Severe plastic deformation such as equal channel angular pressing (ECAP) could change the mechanical and corrosion resistance of Mg alloys. The effects of ECAP extrusion on the mechanical and biodegradable properties of an extruded Mg-1.5Zn-0.5Y-0.5Zr alloy were studied in this work. After two passes and four passes ECAP extrusion, the microstructure, mechanical properties and degradation behaviours were investigated. It showed that with increase of the extrusion pass, the average grain size of the alloy decreased greatly. After four passes extrusion, the grain size was about 1.37 ± 0.22 μm. The ECAP extrusion was beneficial to the ductility of the alloy. With increase of the extrusion pass, the elongation increased from 17% to 27%. However, the ultra-fine grains formation was detrimental to corrosion resistance. For the corrosion rate, compared with the without ECAP extruded samples, the corrosion resistance of the ECAP extruded samples obviously decreased.

The Mg alloy vascular clip has biodegradability and good biocompatibility, which can improve the convenience and safety of clinical application. However, the Mg alloy vascular clip also has some disadvantages, such as an unreasonable structure design and a degradation rate which is too fast. In this study, the process of clamping blood vessels with a biodegradable Mg alloy (Mg-Zn-Nd-Zr and Mg-Zn-Nd) general V-type vascular clip was simulated by finite element simulation software (Abaqus). A new type of vascular clip, the P-type vascular clip, was analyzed and investigated through simulation. The differences between Mg alloy vascular clips of V-type and P-type were analyzed by finite element simulation. In addition, the effects of Zr element on the mechanical properties and corrosion resistance of P-type vascular clips were also investigated to improve the mechanical stability. The results show that during the V-type vascular clip closure of Mg-Zn-Nd-Zr alloy, this clip has some problems, such as uneven distribution of blood vessel stress, crevices in blood vessels and stress concentration. The improved P-type vascular clip has uniform closure, and there is no gap in the blood vessel, which can effectively avoid stress concentration. The improved P-type vascular clip is well closed and can effectively avoid stress concentration. The corrosion resistance of the Mg-Zn-Nd-Zr alloy P-type clip was better than that of the Mg-Zn-Nd alloy P-type clip (degradation rate of 2.02 mm/y and 2.61 mm/y on the 7th day, respectively). Mg-Zn-Nd-Zr alloy The P-type vascular clip remained closed even on the 7th day, which could meet the requirements of clinical application.