About this Abstract |
Meeting |
MS&T21: Materials Science & Technology
|
Symposium
|
Next Generation Biomaterials
|
Presentation Title |
Investigation of Biodegradable Mg-Li Quaternary Alloys with Improved Uniform Degradation |
Author(s) |
Chiamaka Okafor, Norman Munroe |
On-Site Speaker (Planned) |
Chiamaka Okafor |
Abstract Scope |
Magnesium alloys can play an important role in the manufacture of biodegradable implant devices. However, a major challenge of nonuniform degradation remains. Although Mg-Zn-Ca alloys have exhibited superior degradation kinetics and mechanical properties a quaternary element Li is now incorporated to enhance uniform biodegradation behavior. SEM-EDS and XRD analysis were conducted on as-cast alloys. Mechanical properties were assessed by performing tensile tests. Degradation rates were determined by semi-static immersion, potentiodynamic polarization, and electrochemical impedance spectroscopy. A crystal structure change was observed from HCP to BCC as the lithium content increased from 4 wt.% to 11 wt.% with 8 wt.% being a transformation stage. This resulted in increased ductility of about 32 % elongation at 11 wt. % lithium with a slight decrease in strength. Degradations rates decreased with increasing lithium content. Post immersion micrographs revealed absence of pits for alloys with high lithium content. |