Magnesium Alloys and Zinc Alloys as Biodegradable Temporary Implants: Role of Organic Constituents of Body Fluid in Stress Corrosion Cracking

Magnesium (Mg) alloys are great for temporary bone implants as they are strong yet light and have bone-like flexibility, but they dissolve easily in the body, which causes cracking. Zinc (Zn) alloys corrode less but are not so strong. This study investigated how organic molecules like proteins (BSA) and glucose affect the cracking susceptibility of a Mg alloy (ZK60) and a Zn alloy (Zn-1Cu-1Mg). Results showed BSA helped the Mg alloy resist cracking, causing a unique fracture shape. For the Zn alloy, the organic molecules generally enhanced their cracking tendency. This work explains the mechanism behind their different cracking behaviors.