共晶组织强化 NbMoZrVSi_x难熔高熵合金的摩擦磨损性能及磨损机理

In recent years, refractory high-entropy alloys (RHEAs) have gained widespread attention owing to their high structural stability and excellent mechanical properties at both room and elevated temperatures. However, their wear resistance at room temperature is often poor due to their fragility. In this study, the effect of adding small amounts of silicon (Si) to NbMoZrV RHEA on its tribological properties and wear mechanism at room temperature have been studied using various techniques including tribometer, SEM, and XPS. The results showed that adding a moderate amount of Si induced the homogeneous precipitation of a eutectic structure composed of Zr-Zr₃Si phase at the bcc matrix grain boundary. This eutectic structure significantly improved the hardness and wear resistance of the NbMoZrVSi_0.1 RHEA. Unlike the poor tribological behavior observed in NbMoZrVSi_0.05 and NbMoZrVSi_0.2 RHEAs, the NbMoZrVSi_0.1 RHEA exhibited stable coefficient of friction and wear rate under dry sliding wear test at room temperature with varying normal loads. The Zr-Zr₃Si eutectic structure effectively inhibited the initiation and propagation of cracks and brittle spalling during the sliding wear test, resulting in only slight abrasive wear of the NbMoZrVSi_0.1 RHEA. Moreover, the mechanism promoted the subsequent homogeneous oxidation of the worn surface.