Investigation of mechanical properties and antibacterial behavior of WE43 magnesium-based nanocomposite

The aim of this study is to develop a biodegradable magnesium-based nanocomposite with enhanced mechanical and antibacterial properties. To achieve this goal, nano- and micro-scale zinc oxide (ZnO) and copper-zinc oxide (Cu/ZnO) reinforcements were incorporated into WE43 magnesium alloy, as the matrix of the nanocomposite. High purity ZnO and Cu/ZnO were synthesized by solution combustion with citric acid fuel using conventional and microwave heating, resulting in nanometer and micrometer particles, respectively. Friction stir processing (FSP) was employed to develope the magnesium-based composites. ZnO and Cu/ZnO powders were implemented into the WE43 base plate with either drilling holes or machining grooves. Hole-inserted additives resulted in more uniform particle distribution than groove-inserted ones. In addition, nanoscale ZnO and Cu/ZnO particles showed more uniform distribution compared to microscale ZnO. The addition of Cu/ZnO particles yielded the highest level of antibacterial activity, compressive strength and micro hardness of the composite. The antibacterial performance of the composite was in line with the fact that Cu/ZnO powder showed more pronounced antibacterial properties than ZnO powders. In addition, groove-inserted Cu/ZnO composite showed compressive strength of 527 MPa and hardness of 90.7 Hv, which were significantly higher than the values of 300 MPa and 78.7 Hv obtained for groove-inserted ZnO composites. It should be noted that the un-processed monolithic WE43 alloy had a compressive strength of 138 MPa and hardness of 66.8 Hv.