Session Overview |
Friday, May 24 |
16:00 |
Processing of Mg Microtubes for Biodegradable Vascular Stents
* Joung Sik Suh, Korea Institute of Materials Science , South Korea Chang Dong Yim, Korea Institute of Materials Science Magnesium (Mg) alloys are gaining attention as potential metallic biomaterials for temporary biodegradable implants in orthopedic and vascular applications due to their mechanical, electrochemical, and biological properties. However, Mg scaffolds still face challenges such as a high degradation rate, low mechanical properties, and difficult fabrication methods. Processing and alloying are the main approaches for enhancing the overall properties of Mg alloys for biomedical applications. The aim of this study is to develop the process technologies to fabricate patient-specific ultra-precise geometries and achieve the mechanical properties for biodegradable cardiovascular stents. For this reason, a two-step extrusion manufacturing process was developed to fabricate microtubes. This study investigates the microstructure, texture and tensile properties of MZ01 microtubes in terms of extrusion ratio. |
16:30 |
Computational Modelling of Corrosion and Mechanical Performance of Bioabsorbable Magnesium Alloys
* Ted J. Vaughan, University of Galway, Ireland This study investigates the relationship between surface-based corrosion and mechanical degradation of a magnesium WE43 alloy for orthopaedic implants by means of an experimental and numerical approach. Through the development of an enhanced surface-based corrosion framework, this study provided a robust and flexibile framework that could predict the phenomological features of non-uniform pitting corrosion in magnesium-based materials. This model was fully implemented in three dimensions and provided a significant advance on existing models as it enabled the prediction of intricate features of corrosion such as multi-directional pitting and a wide range of pit morphologies. A wide range of corrosion scenarios was evaluated and enabled quantitative relationships to be established between the mechanical integrity and key phenomenological corrosion features. In particular, it was found that the minimal cross-sectional area parameter was the strongest predictor of the remaining mechanical strength (R² = 0.98), with this relationship being independent of the severity or spatial features of localised surface corrosion. This study establishes new mechanistic insight into the performance of the magnesium-based materials undergoing corrosion and could be used to inform the design and development of new bioabsorbable medical implants. |