VLČEK Marián Charles University in Prague

Spoluautoři LUKÁČ František, STULÍKOVÁ Ivana, SMOLA Bohumil, KUDRNOVÁ Hana, VLACH Martin, KODETOVÁ Veronika, SZAKÁCS Gábor, HORT Norbert, KAINER Karl Ulrich

Biodegradable magnesium implants show great promise in improving quality of healthcare and reduction of costs by removing the necessity of a second surgery [1]. The WE43 (Mg-Y-RE-Zr) alloy originally designed for high-temperature applications was recently used as candidate material for biodegradable implants. Furthermore, silver was identified as suitable alloying element for biodegradable magnesium alloys due to its antibacterial properties [2]. Knowledge of microstructure and mechanical properties development with increasing temperature is very important also for applications at ambient temperature, because it determinates Mg-alloys production procedures requiring elevated temperatures. In this work we study novel Mg-Y-Nd-Ag-based materials (total solute content less than 7 wt.%) with various Y and Nd content envisaged for biodegradable implants. Studied alloys were subjected to isochronal annealing with steps 20 K/20 min in as cast condition and also after homogenization annealing. Physical properties and precipitation processes in these alloys were investigated by optical microscopy, scanning electron microscopy, differential scanning calorimetry, electrical resistometry and by microhardness. Response of microhardness to isochronal annealing shows a very good thermal stability of microstructure at least up to 220 °C. Our results are compared to the precipitation processes identified in the WE43 [3] and in the Mg-Ag-Nd-Zr alloy [4]. References: [1] WITTE, F. The history of biodegradable magnesium implants: A review. Acta Biomaterialia, Volume 6, Issue 5, 2010, p. 1680-1692 [2] TIE, D., FEYERABEND F., MÜLLER WD., SCHADE R., LIEFEITH K., KAINER KU., WILLUMEIT R. Antibacterial biodegradable Mg-Ag alloys. European Cells and Materials, Volume 25, 2013, p. 284-298. [3] VLACH, M., SMOLA, B., CÍSAŘOVÁ, H., STULÍKOVÁ, I. Precipitation Processes in Mg-Y-Nd Alloys. Defect and Diffusion Forum, Volumes 334-335, 2013, p.155-160. [4] KIEHN, J., SMOLA, B., VOSTRÝ, P., STULÍKOVÁ, I., KAINER, KU. Micostructure changes in isochronally annealed alumina fibre reinforced Mg-Ag-Nd-Zr alloy. Physica Status Solidi (a), Volume 164, 1997, p. 709-723.