Evaluation of the microstructural evolution of biomedical absorbable Mg alloys during corrosion process through non-destructive 3D analysis using the Absorption Contrast X-ray Tomography (ACT) technique

Abstract

Some Mg alloys have been gaining attention due to the possibility of applications as absorbable biomedical devices. These materials have the ability, once applied to injured tissue in the form of a biomedical device, to undergo the corrosion process concomitantly with the healing process. The possibility of absorption of the material after the aid of the healing process can have a positive impact on the health area by dispensing with the surgery to remove these devices, reducing costs, increasing access to health services in all areas. Although promising, the development of such alloys presents many challenges, which can only be overcome by a careful comparative analysis between the solidification thermal variables, the biocompatibility of the constituent elements, microstructure, mechanical characteristics, and the corrosion behavior of the candidate metal alloys. Among the promising systems, Mg-Si and Mg-Si-Zn stand out due to the roles played by the constituent elements in several enzymatic and structural processes in the human body and the possibility of controlling the corrosion behavior and mechanical properties through the choice of thermal variables of solidification and composition. Due to the nature of its application, the characterization of corrosion behavior must be consistent and robust to provide reliable information and avoid the contradictions found in the literature. In this scenario, the nondestructive 3D characterization technique by X-ray tomography (XCT) is necessary to characterize the evolution of damage in the microstructure due to the advance of the corrosive process, similarly to how it was already extensively employed in the study of Al alloys. (AU)