Preparation and analysis of a biodegradeable magnesium alloy

Abstract

Magnesium alloys offer many possible improvements compared to titanium when used in implants, including the possibility for controlled degradation inside the body. The Institute of Materials Science and Technology at the Technical University of Vienna owns a patent for the use of the Mg-0.6 Ca-0.6 Zn-alloy in bone screws and there is an ongoing activity for research on this topic. This master-thesis starts with the state-of-the-art relevant for the development of a magnesium-calcium-zinc-based biodegradable alloy. The state-of-the-art is divided into the main categories of age-hardening-behavior, the extrusion, the biocompatibility and cytotoxicity as well as the deformation behavior and the intermetallic phases present in magnesium alloys. To understand the thermal behavior, a simulation is carried out using the thermo-kinetic software MatCalc and the findings are discussed. The experimental part spans from the fabrication of the Mg-0.6 Ca-0.6 Zn alloy over different heat-treatments and the successful extrusion and ends at the tensile testing and microscopic analysis of several samples. The tensile tests show promising results and the optical images and transmission electron images allow a sufficient characterization of the microstructure, which is discussed in detail. Although the first round of experiments was a success, some areas still offer space for improvement and before this alloy is ready for implantation, a lot of tests will need to be performed.