Spontaneous passivation in a Rare-Earth-Free Mg4(TiZnSn)3 Multi-Principal element alloy

Abstract Mg 4 (TiZnSn) 3 , a rare-earth-free Mg-based multi-principal element alloy, was synthesized via high-energy ball milling and cold compaction. Potentiodynamic polarization in 0.1 M NaCl revealed spontaneous passivation with a corrosion current density of 8.96 ± 0.83 µA/cm 2 and a nobler than Mg corrosion potential of -1058.35 ± 15.91 mV SCE . X-ray photoelectron spectroscopy confirmed the formation of a mixed oxide film containing ZnO, SnO 2 , and TiO 2 , contributing to the observed passivity. The alloy also exhibited improved mechanical performance, with a hardness of 5.06 ± 0.41 GPa and Young’s modulus of 109.24 ± 10 GPa. These results demonstrate that tailored multi-element alloying and powder metallurgy can synergistically enhance both corrosion resistance and mechanical properties in Mg alloys.