Low-density refractory medium entropy alloys (NbTiVZr, Nb_0.5TiVZr, and NbTiV) were produced by vacuum arc melting, then heat-treated at 1,200°C for 1 h, water quenched, and finally annealed at 500°C for 0.5 h. Their respective microstructures, elevated-temperature (600–1,000°C) mechanical properties, and thermal expansion behavior were then investigated. All the alloys are characterized by a BCC structure with a grain size of c. 85–135 μm. The results demonstrated that NbTiVZr alloy exhibits relatively high yield strength and specific strength at 600, 800, and 1,000°C. Moreover, a low coefficient of thermal expansion was also obtained for this alloy when the temperature was below 750°C. This study provides guidance for the engineering application of low-density refractory medium entropy alloys at elevated temperatures.

低密度耐火介质熵合金（NbTiVZr，Nb _0。通过真空电弧熔化生产5TiVZr和NbTiV），然后在1200°C热处理1小时，水淬火，最后在500°C退火0.5小时。然后研究了它们各自的微观结构，高温（600–1,000°C）的机械性能和热膨胀行为。所有合金的特征都是晶粒尺寸为c的BCC结构。85–135微米。结果表明，NbTiVZr合金在600、800和1,000°C时具有较高的屈服强度和比强度。此外，当温度低于750℃时，该合金的热膨胀系数也低。这项研究为低密度耐火介质熵合金在高温下的工程应用提供了指导。