Microstructure and properties of biodegradable Mg–Zn–Y-Nd alloy micro-tubes prepared by an improved method

Abstract In this study, Mg–Zn–Y-Nd alloy micro-tubes with an outer diameter of ϕ2.46 mm and a wall thickness of 0.14 mm were successfully prepared using an improved technique including hot extrusion with water cooling, multi-pass cold drawing and final annealing treatment. The outer diameter error, inner diameter error and wall thickness error of the cold drawn micro-tubes were 0.58%, 0.36% and 3.43%, respectively. After final annealing at 350 °C for 60 min, the micro-tubes showed refined microstructure with an average grain size of 8.6 μm, a weak texture of the rare earth texture or recrystallization texture, and homogeneously distributed fine second phase particles. The annealed micro-tubes exhibited significantly improved mechanical properties with a yield strength of 240.1 ± 6.0 MPa, an ultimate tensile strength of 319.9 ± 6.0 MPa and a breaking elongation of 22.2 ± 1.0%. Meanwhile, the typical characteristic of ductile morphology could be observed for the fractured specimens. In addition, the annealed micro-tubes also had better corrosion resistance and showed a uniformly corrosion morphology.