This study aimed to develop a novel series of low-density refractory high-entropy alloys (RHEAs) by precipitation strengthening. The design ideas of high-entropy alloys and titanium alloys were combined to develop Ti₃V₂NbAl_0.5, Ti₃V₂NbNi_0.5, and Ti₃V₂NbAl_0.5Ni_0.5 refractory multielement alloys. These alloys displayed low densities of 5.39, 5.83, and 5.55 g/cm³, respectively. The effects of Al and Ni addition on the microstructure and mechanical properties were investigated. Thereinto, the Ti₃V₂NbAl_0.5 with a body-centered cubic structure had a yield strength of 760 MPa, and the compressive strain exceeded 50%. The Ti₃V₂NbNi_0.5 alloy strengthened by large C15 Laves-phase particles in the interdendritic regions exhibited a high yield strength of 1130 MPa but with a limited compressive strain of 20%. By contrast, the Ti₃V₂NbAl_0.5Ni_0.5 alloy had a high yield strength of 1250 MPa and acceptable strain of 40%, benefiting from the precipitation of fine C14 Laves-phase particles and twined B19’ martensite. Moreover, the specific yield strength (SYS) of the Ti₃V₂NbAl_0.5Ni_0.5 alloy was 223 kPa·m³kg⁻¹, superior to most other reported RHEAs at room temperature. It remained a high SYS of 198 and 54 kPa·m³kg⁻¹ at 700 and 800 °C, respectively, which shows a superior balance between its density and mechanical properties across a wide temperature range.

这项研究旨在通过沉淀强化来开发一系列新的低密度耐火高熵合金（RHEA）。结合高熵合金和钛合金的设计思想，开发出Ti ₃ V ₂ NbAl _0.5，Ti ₃ V ₂ NbNi _0.5和Ti ₃ V ₂ NbAl _0.5 Ni _0.5难熔多元合金。这些合金分别显示出5.39、5.83和5.55g / cm ^3的低密度。研究了铝和镍的添加对组织和力学性能的影响。其中，Ti ₃ V ₂ NbAl以体心立方结构为_0.5的屈服强度为760MPa，压缩应变超过50％。在枝晶间区域中由大的C15 Laves相颗粒增强的Ti ₃ V ₂ NbNi _0.5合金具有1130 MPa的高屈服强度，但压缩应变有限，仅为20％。相比之下，受益于细小的C14 Laves相颗粒和孪生B19'马氏体的析出，Ti ₃ V ₂ NbAl _0.5 Ni _0.5合金具有1250 MPa的高屈服强度和40％的可接受应变。此外，Ti ₃ V ₂ NbAl _0.5的比屈服强度（SYS）Ni _0.5合金为223 kPa·m ³ kg ^-1，在室温下优于大多数其他已报道的RHEA。它 在700和800°C时分别保持198和54 kPa·m ³ kg ^-1的高SYS ，这显示出在宽温度范围内其密度与机械性能之间的出色平衡。