Process window and mechanical properties for thin magnesium- and zinc-wires in dieless wire drawing

Due to their biodegradable properties, magnesium- and zinc-based alloys are in the focus of interest for numerous medical applications, e.g. in the form of thin wires. To achieve improved processability by using hot forming and to obtain higher diameter reductions per pass, the dieless wire drawing process is presented in this paper. In order to investigate the processability and the resulting mechanical properties, a selection of magnesium- and zinc-alloys as well as process parameters are chosen, and wire manufacturing is carried out using the dieless drawing process. The resulting process windows and mechanical properties for the selected materials are discussed. It is found that the length of the forming zone is an important indicator for the process window and the cross-sectional area reduction accuracy in the dieless wire drawing process. Furthermore, process parameter variations result in a distinct variation of the mechanical properties of the wires, whereas process temperatures close to the wire extrusion temperature result in mechanical properties similar to the as-extruded wires. Good localization of the deformation is found for forming zones of 25-75 mm length at elevated temperatures and cross-sectional area reductions of up to 30% are possible for Z1 and ZX10 in one drawing step.