Effects of lutetium addition on formation, oxidation and tribological properties of a Zr-based bulk metallic glass

Enhancement of glass-forming ability (GFA) and surface properties are important for the application of Zr-based bulk metallic glasses (BMGs), and surface oxidation is an effective strategy for surface strengthening. In this paper, the effects of rare earth element Lu addition on GFA and oxidation properties of a Zr50Ti2Cu38Al10 bulk metallic glass were studied. The tribological properties of Lu-free and Lu-doping BMGs before and after oxidation were also investigated. It is found that 2 at.% Lu addition in this alloy significantly enhance the critical diameter (dc) from 5 mm to 20 mm. The oxidation rate of 2 at.% Lu-doping alloy is higher than Lu-free alloy, indicating that the addition of Lu facilitates the formation of oxidized scale on the surface of Zr50Ti2Cu38Al10 alloy. Moreover, surface oxidation treatment remarkably improves the wear resistance of Zr50Ti2Cu38Al10 and (Zr0.5Ti0.02Cu0.38Al0.1)98Lu2. This study is beneficial for the improvement of surface properties and further application of Zr-based BMGs.