Predicting and Validating the Performance of Zn-Al-Mg Coatings through an Integrated Thermodynamic, Molecular Dynamics, and Electrochemical Approach.

A combined computational and experimental approach was utilized to investigate the microstructural evolution, electrochemical behavior, and corrosion resistance of hot-dip galvanized Zn-4%Al-5%Mg coating. Thermo-Calc simulations have been used to anticipate phase equilibria and intermetallic formation, while molecular dynamics (MD) simulations helped to understand atomic diffusion mechanisms and corrosion behavior. A complex microstructure, comprising eutectic phases and intermetallic compounds, was analyzed using simulation and experimental approaches. The rapid diffusion of Al into the substrate interface during the process leads to the formation of an interfacial Fe-Al layer between the substrate and the coating. Phases rich in MgZn2 played a crucial role in enhancing passivation and promoting the formation of a protective oxide layer. Additionally, the preferential formation of corrosion products involving Mg during the initial stages of exposure was also confirmed. This study highlights the effectiveness of combining Thermo-Calc and MD simulations to optimize hot-dip galvanized formulations, minimize experimental uncertainties, and accelerate material development.