Mechanical Properties of Zinc Alloy Zn–1Ag–1Cu Processed by Equal–Channel Angular Pressing and Extrusion

Abstract

Zinc biodegradable alloys are actively researched as promising materials for creating biomedical implants for osteosynthesis and vascular stents. New zinc alloys of the Zn–Ag–Cu system are of particular interest due to their antimicrobial and bactericidal properties conferred by the addition of silver and copper. The feasibility of producing a defect-free zinc alloy spoke and the influence of combined processing, involving severe plastic deformation techniques, such as equal-channel angular pressing (ECAP) and extrusion, on the microstructural changes and mechanical properties of the Zn 1 wt % Ag 1 wt % Cu (Zn–1Ag–1Cu) alloy were studied. To complement the experimental study, computer modeling of the extrusion of the Zn–1Ag–1Cu alloy at a temperature of 150°C was performed. Data on the distribution of accumulated deformation and average stresses were obtained, indicating structural relaxation. Multipass ECAP treatment resulted in a significant grain refinement to 3 ± 0.5 μm compared to the homogenized state with a grain size of 326 ± 31 μm, while subsequent extrusion led to recrystallization. After combined processing, the average grain size increased to 13 ± 2 μm. Samples subjected to ECAP exhibited a substantial increase in ultimate strength to 204 MPa and ductility to 50%, compared to the homogenized state (78 MPa, 12%). However, extruded samples showed a slight decrease in strength to 181 MPa and ductility to 29%. It was concluded that the combined deformation techniques enable the production of a defect-free spoke with a diameter of 5 mm and a length of 200 mm, exhibiting mechanical properties suitable for medical applications.