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-xYx (x=0, 1, 3, 5, 7, 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-xYx samples are completely composed of amorphous structure. With increasing Y content from 1 at% to 9 at%, the ΔTx and Trg of the (Cu56Zr44)1-xYx 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-xYx amorphous 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 N 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 1 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-xYx 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-xYx 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. © 2021, Science Press. All right reserved.