Microstructure characterization and corrosion resistance in soil of Mg-2Zn-xCe-yCu alloy for light agricultural machinery

Abstract

The microstructure, mechanical properties, corrosion behavior, and potential for lightweight applications of Mg-2Zn alloys enhanced with Cu and Ce were investigated. It was observed that the Ce and Cu-containing phases displayed various morphologies in the as-cast and extruded conditions. The extruded alloy, containing 0.8 wt% Ce and 0.5 wt% Cu, exhibited optimal mechanical properties, with the yield strength of 289 MPa, ultimate tensile strength of 336 MPa, and elongation of 15.8 %. Grain boundary and precipitation strengthening significantly contributed to the increase in yield strength. After four months of soil burial, the specimen surface showed localized pits and cracks, likely serving as anodes in the areas including Ce and Cu-containing phases. The corrosion rates in different soil environments paddy, vegetable, orchard, and corn fields were 2.029, 2.293, 2.133, and 1.986 mg·cm−2·d−1, respectively indicating variations due to complex soil conditions. The corrosion products included Mg(OH)2 and Mg5(CO3)4(OH)2·4 H2O, among others, throughout the burial period. Furthermore, model assembly in SolidWorks and static structural simulation with ANSYS confirmed the alloy's reliable load-bearing capacity, safety, and potential as the material for lightweight agricultural machinery.