Effect of Extrusion Temperature on the Microstructure, Mechanical Properties, and In Vitro Corrosion Behavior of a Biodegradable Mg-Zn-Ca-Mn-Sn Alloy

Magnesium-based alloys have great potential in biodegradable implant materials. However, their low strength and high corrosion rate limit their application. The main objective of this study is to investigate the effect of extrusion temperature on the microstructure, mechanical properties, and in vitro corrosion behavior of Mg-1.2Zn-0.4Ca-0.4Mn-0.5Sn alloy. The results show that the extruded alloy mainly contains α-Mg and CaMgSn phases. The CaMgSn phase is distributed on the magnesium matrix along the extrusion direction. As the extrusion temperature decreases, the grains become more refined and the tensile strength of the material increases significantly. The latter is due to the combined effect of fine grain strengthening, precipitation strengthening, and work hardening. The main products of corrosion in a simulated body fluid are Ca₃(PO₄)₂ and Mg(OH)₂. Extruding the material at 360 °C results in excellent mechanical properties (tensile strength of 272 MPa, elongation at break of 21.1%) and corrosion resistance (corrosion rate of 0.113 mm/y). The paper also discusses the relationship between the microstructure and the mechanical properties and corrosion behavior.