Tribological and corrosion behaviors of Mg56.5Cu27Ag5Dy11.5 bulk metallic glass in NaCl solution

Abstract

In this study, the tribological behaviors of Mg56.5Cu27Ag5Dy11.5 bulk metallic glass (BMG) in air and NaCl solution were investigated using ball-on-disk reciprocating friction. The Mg56.5Cu27Ag5Dy11.5 BMG exhibits higher strength and hardness than those of commercial AZ31B alloy and pure Mg. The wear rate of the Mg56.5Cu27Ag5Dy11.5 in air is 3.8×10−7mm3·mm−1·N−1, which is superior to those of AZ31B alloy (7.3×10−7mm3·mm−1·N−1) and pure Mg (6.5×10−7mm3·mm−1·N−1). The wear mechanism of Mg56.5Cu27Ag5Dy11.5, AZ31B, and pure Mg sliding in air is dominated by oxidation and abrasive wear. The wear rates of alloys in NaCl decrease in the following order: 8.3×10−7mm3·mm−1·N−1 for pure Mg, 6.3×10−7mm3·mm−1·N−1 for AZ31B, and 5.4×10−7mm3·mm−1·N−1 for Mg56.5Cu27Ag5Dy11.5. The Mg56.5Cu27Ag5Dy11.5 and pure Mg demonstrate inferior corrosion resistance in NaCl to that of AZ31B. Thus, the Mg56.5Cu27Ag5Dy11.5 and pure Mg subject to tribocorrosion controlled by synergistic effects of abrasive and corrosive wear, which results in a large wear rate during sliding in NaCl. The possible mechanism of corrosion accelerating wear deterioration is discussed, which provides the guidance for the improvement in the tribocorrosion resistance of Mg-based BMGs for further load-bearing applications.