Ti-Al基合金是一种具有较高强度/密度比，但成型性能较差的航空航天材料。为进一步优化该类合金，使其适用于粉末冶金的成分设计，本工作采用预合金粉末放电等离子烧结工艺制备了名义成分为Ti-22Al-25Nb和Ti-22Al-25Nb-1V的Ti₂AlNb合金，通过XRD、SEM、TEM、EBSD和Vickers硬度测试等方法，系统研究了V的添加对Ti₂AlNb合金的微观组织及硬度的影响。结果表明，相较于未掺V合金，掺V合金的显微硬度明显提高，并在时效温度为850 ℃时达到最高值503 HV。硬度提高主要是由于V的添加使得B2相晶粒细化，O/α₂相宽度减小以及晶格畸变引起的位错缠结所导致的。其中V原子部分取代了B2相中的Nb原子，导致B2相晶格常数减小，进而诱发晶格畸变。另外V和Nb原子在B2相中的偏析会诱导形成“弯曲”组织B2 (富Nb和V) + α₂ (贫Nb和V)，从而进一步提高掺V合金的硬度。

Ti₂AlNb-based alloys, as emerging lightweight high-temperature structural materials, have shown great potential for aerospace applications owing to their outstanding creep resistance, strong plasticity, and impressive high-temperature oxidation resistance. However, the material has yet to see widespread use owing to its poor formability and processability. Compared to traditional melting and forging methods, powder metallurgy has proven to be an effective method for preparing this alloy with a required shape, thereby circumventing phase transformation during hot working. The properties of Ti₂AlNb-based alloy can be enhanced by adding stabilized elements to the B2 or α₂ phase. Among these metallic elements, V has been demonstrated to effectively increase the ductility and high-temperature strength of Ti₂AlNb-based alloys. However, the mechanism of the V addition's effect on the microstructure and properties of Ti₂AlNb-based alloys during aging treatment has not been systematically clarified. Therefore, investigating the influence of powder sintering and post-heat treatment on the microstructure and properties of Ti-22Al-25Nb-1V alloys is crucial for accelerating their industrialization process. This investigation forms the basis of this work. A detailed study on the role of V in the microstructure and deformation responses of the Ti₂AlNb alloy was performed. This involved preparing V-added and V-free Ti-22Al-25Nb alloys via spark plasma sintering. Then, the sintered alloys were solution treated at 1300 ^oC for 4 h and subsequently aged at temperatures from 800 ^oC to 1050 ^oC for 2 h for microstructure modification. The detailed microstructure of the alloys was analyzed using X-ray diffraction and electron microscopy. The results revealed that by adding V, the volume fraction of the residual α₂ phase improves. The microhardness of the V-doped alloys is significantly enhanced compared to the undoped alloys and reached a maximum value of 503 HV at an aging temperature of 850 ^oC. This α₂ phase pins the grain boundary during heat treatment, resulting in an alloy with a refined grain size. Additionally, V additions can inhibit the B2 + α₂ → O transition, promoting a finer O/α₂ phase precipitate and higher hardness. Furthermore, microstructural analysis proved that the segregation of V and Nb in the B2 phase will cause the “curved” structure, including Nb- and V-rich B2 and Nb- and V-lean α₂ phases. The partial replacement of Nb by V reduced the lattice parameter in the B2 phase, which further improves the hardness of this alloy.