原位陶瓷增强TaMoTiCr难熔高熵合金复合材料的宽温域摩擦学性能

Wide-Temperature-Range Tribological Properties of In Situ Ceramic-Reinforced TaMoTiCr Refractory High-Entropy Alloy Composites

摘要:

通过放电等离子烧结技术制备了原位陶瓷相增强的TaMoTiCr难熔高熵合金复合材料，并分别添加2.5wt%和5.0wt%的h-BN。结果表明：h-BN的添加促进了(Ti, Ta)N、TaB₂和MoB陶瓷相在体心立方基体中的均匀形成，使显微硬度显著提升至1136.95 HV。摩擦学测试结果表明：添加2.5wt% h-BN的复合材料在室温下表现卓越，磨损率低至1.64×10^-7 mm³?N^-1?m^-1；而添加5.0wt% h-BN的复合材料在300 ℃时性能最优。在800 ℃以上高温条件下，材料表面形成了富含Cr₂O₃、TiO₂和B₂O₃的润滑氧化摩擦层，有效降低了摩擦与磨损。添加2.5wt% h-BN的复合材料在1000 ℃时磨损率仅为5.22×10^-7 mm³?N^-1?m^-1。该原位陶瓷增强策略显著提升了难熔高熵合金在宽温域内的耐磨性能，为先进航空航天应用提供了重要技术路径。

Abstract:

In-situ ceramic phase-reinforced TaMoTiCr refractory high-entropy alloy (RHEA) composites were prepared by spark plasma sintering with the addition of 2.5wt% and 5.0wt% h-BN, separately. Results show that the h-BN promotes the uniform formation of (Ti, Ta)N, TaB₂, and MoB ceramic phases within the body-centered cubic matrix, significantly increasing microhardness to 1136.95 HV. Tribological test results show that the composite with the addition of 2.5wt% h-BN presents great performance at room temperature with an ultra-low wear rate of 1.64×10^-7 mm³?N^-1?m^-1, while the composite with the addition of 5.0wt% h-BN shows optimal performance at 300 °C. Above 800 °C (elevated temperature condition), lubricious oxide tribolayers, rich in Cr₂O₃, TiO₂, and B₂O₃, form on the material surface, effectively reducing friction and wear. At 1000 °C, the composite with the addition of 2.5wt% h-BN achieves a wear rate of 5.22×10^-7 mm³?N^-1?m^-1. This in situ ceramic reinforcement approach effectively enhances wear resistance of RHEAs across a wide temperature range, offering great potential for advanced aerospace applications.