Effect of Y-doping on Glass Forming Ability and Tribological Properties of (Cu56Zr44)1-xYx Alloys

In order to develop a new type of amorphous alloy whose composition is far away from the eutectic point of Cu56Zr44 and explore a new piston material used in biomass fuel new energy vehicle, (Cu56Zr44)(1-x)Y-x (x=0, 1, 3, 5, 71, 9, at%) samples were prepared by the single-roller rapid quenching. The phases, thermodynamic parameters and nano-hardness of the samples were characterized, as well as the tribological properties of the samples under ethanol-gasoline diluted engine oil lubrication were measured. The results show that (Cu56Zr44)(1-x)Y-x samples are completely composed of amorphous structure. With increasing. Y content from 1 at% to 9 at%, the Delta T-x and T-rg of the (Cu56Zr44)(1-x)Y-x amorphous sample decrease from 61 K to 51 K and 0.670 to 0.658, respectively, but are still higher than 49 K. and 0.644 of Cu56Zr44 amorphous sample, i.e., the glass forming ability (GFA) and thermal stability of Cu56Zr44-based alloy are enhanced by Y doping. With increasing Y content from 1 at% to 9 at%, the nano-hardness of (Cu56Zr44)(1-x)Y-x amorphons sample decreases from 8.83 GPa to 7.33 GPa (higher than 6.82 GPa of Cu56Zr44). The friction coefficient and wear rate at 10 and 20 IV loads increase (lower than the ones of Cu56Zr44), i.e., the mechanical and tribological properties. of Cu56Zr44-based alloy are significantly improved by Y doping, furthermore, the at% Y sample has the strongest GFA and thermal' stability, also shows the best anti-friction and wear-resistance performance. At the same experimental conditions, the friction coefficient and wear rate of (Cu56Zr44)(1-x)Y-x amorphous samples are lower than those of ZL109 Al alloy. The highest reduction of wear rates are as high as 98.62% and 97.79% at the two loads, namely (Cu56Zr44)(1-x)Y-x amorphous alloy possesses more excellent anti-friction and wear-resistance performance than ZL109 Al alloy under ethanol-gasoline dilution engine oil lubrication, which also provides a certain theoretical and experimental guidance for the research and development of a new piston material used in biomass fuel-fueled new energy automobile.