Abstract:Biodegradable wires, able to provide load-bearing support for various biomedical applications, are the novel trends in current biomaterial research. A thin 99.92% Mg wire with a diameter of 250 μm was prepared via direct extrusion with an extreme reduction ratio of 1:576. The total imposed strain in a single processing step was 6.36. Extrusion was carried out at elevated temperatures in the range from 230 to 310 °C and with various ram speeds ranging from ~0.2 to ~0.5 mm/s. The resulting wires show very good mechanical properties which vary with extrusion parameters. Maximum true tensile stress at room temperature reaches ~228 MPa and ductility reaches ~13%. The proposed single-step direct extrusion can be an effective method for the production of Mg wires in sufficient quantities for bioapplications. The fractographic analysis revealed that failure of the wires may be closely connected with inclusions (e.g., MgO particles). The results are essential for determining the optimal processing conditions of hot extrusion for thin Mg wire. The smaller grain size, as the outcome of the lower extrusion temperature, is identified as the main parameter affecting the tensile properties of the wires.

Key words: biomedical materials; mechanical properties; fracture; nonferrous metals; magnesium