Refractory high-entropy alloys (RHEAs) hold far reaching application potential in high temperature structural materials fields due to their high melting points and excellent softening resistance. However, the trade-off between strength-ductility and oxidation resistance of RHEAs has become a critical problem for their processing and application. In this work, we reported a strategy to enhance ductility of NbNiTaTi RHEA by applying the eutectic reaction of NiTi shape memory alloys. Experimentally, NbNiTaTi RHEA exhibited BCC phase and eutectic structure composed of IM phase and NiTi_B2 phase. The RHEA showed a compressive strength of 2140 ± 30 MPa and a compressive plastic strain of 34 ± 2% at room temperature. Actually, the ultrafine eutectic structure with ductile NiTi_B2 phase and hard IM phase could greatly enhance the ductility of NbNiTaTi RHEA while ensuring its strength. Meanwhile, The BCC phase with high solidification temperature remedied the weakness of high temperature stability of RHEA after adding non-high melting point elements. Besides, NbNiTaTi RHEA showed good corrosion resistance and its passive film remained stable across a wide range of potential. These results provided theoretical guidance for the application of ductile phase in RHEA field.

耐火高熵合金（RHEAs）由于其高熔点和优异的抗软化性，在高温结构材料领域具有深远的应用潜力。然而，RHEA的强度-延展性和抗氧化性之间的权衡已成为其加工和应用的关键问题。在这项工作中，我们报道了一种通过应用 NiTi 形状记忆合金的共晶反应来提高 NbNiTaTi RHEA 延展性的策略。实验上，NbNiTaTi RHEA 呈现出 BCC 相和由 IM 相和 NiTi _B2相组成的共晶结构。RHEA 在室温下显示出 2140 ± 30 MPa 的抗压强度和 34 ± 2% 的压缩塑性应变。实际上，具有延展性 NiTi _{B2的超细共晶结构}相和硬 IM 相可以在保证强度的同时大大提高 NbNiTaTi RHEA 的延展性。同时，高凝固温度的BCC相弥补了添加非高熔点元素后RHEA高温稳定性的不足。此外，NbNiTaTi RHEA 表现出良好的耐腐蚀性，其钝化膜在很宽的电位范围内保持稳定。这些结果为韧性相在RHEA领域的应用提供了理论指导。