How alloying and processing effects can influence the microstructure and mechanical properties of directly extruded thin zinc wires

Abstract

Zinc (Zn) in particular has gained attention as biodegradable metal due to its advantageous corrosion rates compared to magnesium (Mg) or iron (Fe). Still, strength and ductility of zinc are found to be unfavorable for many medical applications. Strategies to overcome such issues base on a distinct grain refinement of the respective product. One important condition of the metal is assumed to be in the form of wires, which in the present work stem from a direct extrusion setup and high degrees of deformation, therefore a hot forming procedure as the underlying thermomechanical treatment. A basic binary alloying approach with Mg, manganese (Mn) and copper (Cu) is applied, limiting the content to a solid solution range of the alloys. The processability and the processing ranges are examined as well as their impact on the microstructure development and the resulting mechanical behavior. Higher extrusion speed leads to inhomogeneous material flow during extrusion. Alloying Zn can reduce the influence of process parameters and decrease the average grain sizes of wires which experienced lower temperature impact. The forming ability of pure Zn and ZnMg-alloy remain limited whereas they appear more beneficial for the alloys with Mn and especially Cu.