Corrosion Response of Twin Roll Cast AZ31 Alloy in Biologically Relevant Environments

The present work highlights twin-roll cast (TRC) AZ31 magnesium alloy as an energy-saving processing alternative to conventional ingot-cast AZ31 magnesium alloy through analytical characterization, corrosion behaviour in in-vitro biologically relevant environments for degradable implant applications. Conventional AZ31 magnesium alloy is a standard lightweight and bone-matching alloy for implants, it is still far from field applications due to rapid corrosion, hydrogen buildup under physiological conditions, and pitting corrosion. The present study focuses solely on the microstructural characteristics and not the cytotoxic effect of the TRC AZ31 magnesium alloy. 0.9% NaCl and Ringer’s solution were used to identify the role of the diffusion layer over pitting, while simulated body fluid (SBF) was used for mimicking in-vitro physiological conditions that curb pitting and hydrogen evolution. Potentio-dynamic polarization was used to study the corrosion behaviour, hydrogen evolution studies were done, micro-hardness testing was performed for microstructure comparison, secondary electron microscopy was implemented to understand the diffusion barrier formation, and energy-dispersive X-ray spectroscopy was used for elemental analysis. Overall, these insights show how microstructure, environment, and corrosion interact, for broader biomedical adoption of AZ31 alloy.