Microstructural, mechanical and corrosion characterization of an as-cast Mg–3Zn–0.4Ca alloy for biomedical applications

Abstract

The as-cast Mg–3Zn–0.4Ca alloy shows a great potential to be used in biomedical applications due to its composition, mechanical properties and biodegradability. Zn and Ca appear naturally in the organism accomplishing vital functions. The alloy consists of an α-Mg matrix and a eutectic composed of α-Mg + Ca2Mg6Zn3. The eutectic product enhances the mechanical properties of the studied alloy, causing strengthening and providing superior hardness values. In this alloy, cracks initiate at the intermetallic compounds and progress through the matrix because of the open network formed by the eutectics. Attending to the corrosion results, the eutectic product presents a noble potential compared to the α-Mg phase. For this reason, the corrosion progresses preferentially through the matrix, avoiding the (α-Mg + Ca2Mg6Zn3) eutectic product, when the alloy is in direct contact to Hank's solution.

Keywords

• Mg–Zn–Ca alloys
• Biomaterials
• Biodegradable implants
• Nanoindentation
• Three-point bending test
• Corrosion behaviour