The aim of this doctoral thesis is to begin the development of thin magnesium wires for implant applications. It consists of finding the suitable alloy and discussing the possibilities to prepare the wire via direct extrusion. This includes characterization of the microstructure, impurities, mechanical properties, processing conditions, twinning and texture-related anisotropy. A method for effective preparation of thin pure magnesium wires is presented and the effect of processing parameters on the wire properties is studied. An attempt was made to utilize dispersion of quasicrystalline icosahedral phase to obtain better alloys. Due to the difficulties that arise with extensive alloying and subsequent production of thin wires a Mg-0.4Zn alloy was chosen as the initial material. The results of corrosion tests in artificial body fluids made necessary the employment of a coating that slows down the initial degradation processes and makes further surface functionalization possible. A copolymer of L-lactide and ε-caprolactone is used to further improve the corrosion properties of the wires. To overcome the variation in tensile properties connected with occasional MgO impurity, wire ropes are braided. Based on the results, these ropes could be potentially used for sternal fixation in pediatric patients, where the physiologic loads on the sternum are not as severe as for adults. A possibility of a biodegradable sternal fixation would be beneficial to minimize post-sternotomy pain syndrome and suppress complications when multiple open-heart surgeries are required.
(seminar organized by the Department of Dielectrics)