In the present study, phase stability and compressive mechanical properties of the (Zr₅₀Ti₃₅Nb₁₅)_100-xAl_x (x = 0 to 30 at.%) high-entropy alloys were investigated. It was found that the crystalline structure of cast alloys changed from the initial disordered body-centered cubic (BCC) structure to an ordered body-centered cubic (B2) structure as the Al concentration was increased. Their microstructure and phase evolution after long-term annealing up to 1000 h at temperature ranging from 900 °C to 1100 °C were analyzed. Annealing has no obvious influence on the matrix phase of Zr₅₀Ti₃₅Nb₁₅, which keeps BCC structure during all the annealing processes. For the alloys (Zr₅₀Ti₃₅Nb₁₅)₈₀Al₂₀ and (Zr₅₀Ti₃₅Nb₁₅)₇₀Al₃₀ with higher Al content, secondary phase (Al₃Zr₅) precipitates after annealing at 900 °C. With the increasing annealing temperature to 1000 °C or 1100 °C，there is a tendency that the amount of the Al₃Zr₅ phase decreases slightly, indicating that Al₃Zr₅ phase is unstable at high temperature. Accompanied by the phase change, there were also corresponding variations in compressive properties. The secondary phase precipitated in the (Zr₅₀Ti₃₅Nb₁₅)₈₀Al₂₀ and (Zr₅₀Ti₃₅Nb₁₅)₇₀Al₃₀ decreases the compressive plasticity, but has little influence on the yield strength. Meanwhile, the compressive properties of as-cast (Zr₅₀Ti₃₅Nb₁₅)₉₀Al₁₀ and (Zr₅₀Ti₃₅Nb₁₅)₈₅Al₁₅ were also tested to investigate the effect of Al content on the yield strength. Our findings provide a new insight in developing low-density high entropy alloys containing Al.

在本研究中，研究了 (Zr ₅₀ Ti ₃₅ Nb ₁₅ ) _100-x Al _x (x = 0 to 30 at.%) 高熵合金的相稳定性和压缩力学性能。研究发现，随着Al浓度的增加，铸造合金的晶体结构从最初的无序体心立方（BCC）结构转变为有序体心立方（B2）结构。分析了它们在 900°C 至 1100°C 温度范围内长期退火 1000 小时后的微观结构和相演变。_{退火对Zr 50} Ti ₃₅ Nb ₁₅的基体相无明显影响，在所有退火过程中保持 BCC 结构。对于Al含量较高的合金(Zr ₅₀ Ti ₃₅ Nb ₁₅ ) ₈₀ Al ₂₀和(Zr ₅₀ Ti ₃₅ Nb ₁₅ ) ₇₀ Al ₃₀ ，在900℃退火后会析出第二相(Al ₃ Zr _{5 )。}随着退火温度升高到 1000 ℃或 1100 ℃，Al ₃ Zr ₅相的量有轻微减少的趋势，表明 Al ₃ Zr ₅相在高温下不稳定。伴随着相变，压缩性能也出现了相应的变化。_{在(Zr 50} Ti ₃₅ Nb ₁₅ ) ₈₀ Al ₂₀和(Zr ₅₀ Ti ₃₅ Nb ₁₅ ) ₇₀ Al ₃₀中析出的二次相降低了压缩塑性，但对屈服强度几乎没有影响。同时，铸态 (Zr ₅₀ Ti ₃₅ Nb ₁₅ ) ₉₀ Al ₁₀和 (Zr ₅₀ Ti ₃₅ Nb₁₅ ) ₈₅ Al ₁₅也进行了测试，以研究 Al 含量对屈服强度的影响。我们的研究结果为开发含铝的低密度高熵合金提供了新的见解。