Magnesium alloy AZ91 is one of the best suited biodegradable biomaterials for bioimplants. Magnesium is a highly active metal with accelerated corrosion in physiological environments. AZ91 alloy has two distinct phases in the matrix, which form galvanic couple inducing micro galvanic corrosion (primary phase anodic with respect to the secondary phase) in the alloy. However, the corrosion rate could be controlled by tailoring the microstructure of the alloy. The distribution and dispersion of secondary phase particles greatly influence the corrosion rate of the material. A numerical model was developed using Comsol Multiphysics® to study the effect of distribution of secondary phase on the corrosion rate of the alloy. The average anodic current density was found to be higher for AZ91 with continuous network secondary phase microstructural configuration. The average anodic corrosion current and the corrosion rate were found to be lower for AZ91 with dispersed secondary phase microstructural configuration. The numerical modelling results were found to be consistent with the experimental results available in the literature.
Vaira Vignesh R. and Dr. Padmanaban R., “Modelling Corrosion Phenomenon of Magnesium Alloy AZ91 in Simulated Body Fluids”, in Advances in Mathematical Methods and High Performance Computing, vol. 41, V. K. Singh, Gao, D., and Fischer, A., Eds. Cham: Springer International Publishing, 2019, pp. 471–486.