Three-dimensional analysis of the microstructure and bio-corrosion of Mg-Zn and Mg-Zn-Ca alloys

The effects of the morphology and the distribution of secondary phases on the bio-corrosion properties of magnesium (Mg) alloys are significant. Focused Ion Beam (FIB) tomography and Micro X-Ray computed tomography (Micro-CT) have been used to characterise the morphology and distribution of (α-Mg + MgZn) and (α-Mg + Ca₂ + Mg₆ + Zn₃) eutectic phase mixtures in as-cast Mg-3Zn and Mg-3Zn-0.3Ca alloys, respectively. There were two different 3D distributions: (i) an interconnected network and (ii) individual spheres. The tomography informed our understanding of the relationship between the distribution of secondary phases and the development of localized corrosion in magnesium alloys.