Mechanical properties and corrosion resistance of hot extruded Mg-2.5Zn-1Ca alloy

It is demonstrated that the mechanical properties and corrosion resistance of Mg-2.5 wt%Zn-1 wt%Ca alloy are enhanced by the microstructural changes imparted by hot extrusion. A processing procedure is developed to form hollow tubes with an outer diameter of ∼2.0 mm and wall thickness of ∼0.1 mm, which is well suited for subsequent stent manufacturing. The influence of thermal and mechanical processing on corrosion and plasticity was found to be associated with grain-size reduction and the redistribution of intermetallic particles within the microstructure, providing significant improvement of performance over the cast alloy. Observation of the fracture surfaces reveals a mode transition from brittle (cast) to ductile (processed). Enhanced mechanical properties and decreased resorption rate represent significantly improved performance of this alloy after the novel processing sequence. Based on the improved properties, the produced Mg alloy is more suitable for practical in vivo applications.