Abstract: Wear resistance is a critical consideration in engineering applications. In this study, we demonstrated an Ir-Ta-Ni-Nb bulk metallic glass (BMG) with outstanding high-temperature wear resistance and revealed its promising applications in extreme environments. The wear behavior and mechanism were systematically investigated from room temperature (RT) to 750 °C. The results show that the wear rate increases from ∼2.65 × 10^-6 mm³ N^-1 m^-1 to ∼10.56 × 10^-6 mm³ N^-1 m^-1 in the temperature span RT to 400 °C, following abrasive wear and flash temperature-induced oxidative wear during the friction. However, at the higher temperature of 600 °C, further heating due to frictional heat leads to a softening of the wear surface, resulting in a maximum wear rate of ∼20.99 × 10^-6 mm³ N^-1 m^-1 under softness-driven abrasive wear as well as oxidative wear. Interestingly, the wear resistance at an even higher temperature of 750 °C shows a paradoxical improvement of ∼7.08 × 10^-6 mm³ N^-1 m^-1, which is attributed to the formation of an oxide layer with a thickness of several microns, avoiding violent wear of BMG. The results demonstrate the unreported outstanding high-temperature wear resistance of the Ir-Ta-Ni-Nb BMG, especially its excellent capability to resist wear at 750 °C, leading to the promising applications of BMG in the fields of aerospace, metallurgy, and nuclear industries.

Key words: High-temperature alloy, Superior wear resistance, Wear mechanisms, Bulk metallic glass