The Synergistic Effect of Two Alloying Elements on the Microstructures and Properties of Zn–2.5Al–3Mg Alloys

Abstract

The present study investigates the microstructure, hardness, and corrosion behavior of Zn–2.5Al–3Mg alloys with the addition of two elements (Zr–Si, Zr–Sb, and Zr–Ti). This analysis includes SEM/EDS, Brinell hardness testing, electrochemical measurements, and XPS. The SEM results indicate that the Zn–2.5Al–3Mg alloy, with added Zr and Ti elements, exhibits finer grains and a more homogeneous structure compared to the other two combinations (Zr–Si and Zr–Sb). Electrochemical analysis indicated that the Zn–2.5Al–3Mg–0.2(Zr–Ti) alloy exhibited the best corrosion resistance among all the samples tested. Furthermore, XPS identified that the corrosion products of the Zn–2.5Al–3Mg–0.2(Zr–Ti) alloy mainly consist of dense Zn₅(OH)₆(CO₃)₂, ZnAl₂O₄, and MgAl₂O₄. An exploration into the corrosion resistance mechanism of the Zn–2.5Al–3Mg–0.2(Zr–Ti) alloy showed that the dense corrosion products formed during the corrosion process gradually accumulate and fill corrosion gaps. This accumulation hinders the progression of corrosion into the metal, ultimately enhancing the alloy's corrosion resistance.