Ti元素对NbTaMoWTix难熔高熵合金组织、性能及热稳定性的影响

Effect of Element Ti on Microstructure, Properties, and Thermal Stability of NbTaMoWTix Refractory High-Entropy Alloys

摘要:

研究了Ti元素对NbTaMoWTi_x (x=0, 1, 1.5, 2) 难熔高熵合金铸造态和退火态组织和力学性能的影响。结果表明：加入Ti后，铸造态合金仍然保持原有的体心立方（bcc）结构；力学性能方面，对比未加入Ti元素的NbTaMoW合金，强度和塑性分别提高了93%和215%。NbTaMoWTi_x合金表现出优异的热稳定性。在经过1400 ℃退火处理后，仍然可以保持bcc单相结构，力学性能甚至略有提升。然而，高Ti含量合金（NbTaMoWTi_1.5与NbTaMoWTi₂）经过退火处理后，由于富Ti针状相的出现，力学性能明显下降。

Abstract:

The effect of element Ti on the microstructures and mechanical properties of as-cast and annealed NbTaMoWTi_x (x=0, 1, 1.5, 2) refractory high-entropy alloys (RHEAs) was investigated. Results show that after Ti addition, the as-cast alloys maintain their original single body-centered cubic (bcc) structure. As for the mechanical properties, compared with those without Ti addition, the strength and ductility of NbTaMoWTi_x alloys increase by 93% and 215%, respectively. Furthermore, the NbTaMoWTi_x alloys exhibit outstanding thermal stability. After annealing at 1400 °C, they still maintain the single bcc structure, and their mechanical properties are even slightly improved. However, annealing leads to a significant deterioration in the mechanical properties of high-Ti-content alloys (NbTaMoWTi_1.5 and NbTaMoWTi₂), owing to the formation of Ti-rich acicular phases.