A new approach to plastic deformation of biodegradable zinc alloy with magnesium and its effect on microstructure and mechanical properties

The plastic deformation of biodegradable zinc alloy with 1 wt% of magnesium by hydrostatic extrusion (HE) was performed. The influence of severe plastic deformation on the microstructure and mechanical properties of ZnMg was investigated. Cumulative extrusion with total true strain ε = 3.33 was applied to the homogenised material. Microstructure observations carried out using scanning electron microscope (SEM)/ Electron Backscatter Diffraction (EBSD) methods, as well as static tensile tests, revealed outstanding results. After the deformation, grain refinement causing substantial strengthening of the material was observed. An average grain size equal to 700 nm and YS = 316 MPa, UTS = 435 MPa with εf = 35% was obtained. These results indicate that the HE method enables the grain refinement level and mechanical properties of ZnMg to be obtained, which would not be possible with conventional methods of plastic deformation. The properties of the Zn alloy after HE satisfy the requirements for bioresorbable stent applications.