A new 3d transition metal high entropy alloy (3d TM HEA) CoFeNiTiV was prepared by vacuum arc-melting. The phase component, microstructure and mechanical properties of CoFeNiTiV alloy were investigated thoroughly, with the comparison of CoFeNiTi-base alloys. The results show that both CoFeNiTiV and CoFeNiTiAl consists of a typical single bcc phase, while the CoFeNiTiCr and CoFeNiTiCu alloys are both composed of a single fcc phase although they are all CoFeNiTi based alloys. The effectiveness of VEC has been confirmed in the studied alloy system. From the perspective of the elemental role on microstructure, Ti is beneficial to the formation of compounds, while the elemental V, Cu, Al or Cr promote the formation of single-phase solid solution. Moreover, the yield strength reaches 2730 MPa and ultimate compressive strength of CoFeNiTiV alloy is up to 3890 MPa, which is the highest of all CoFeNiTi based HEAs, even of all 3d TM HEAs up to date. Meanwhile, it exhibits a good ductility of 21.3%. This excellent strength-ductility synergy of CoFeNiTiV alloy might stem from the majority constitution of bcc phase, solid-solution strengthening, the strong bonding among the principal elements and the inhabitation of cracking nucleation owing to the uniform solute distribution.

通过真空电弧熔炼制备了一种新型的3d过渡金属高熵合金（3d TM HEA）CoFeNiTiV。通过对CoFeNiTiV基合金的比较，深入研究了CoFeNiTiV合金的相成分，显微组织和力学性能。结果表明，CoFeNiTiV和CoFeNiTiAl均由典型的单一bcc相组成，而CoFeNiTiCr和CoFeNiTiCu合金均由单一fcc相组成，尽管它们都是基于CoFeNiTi的合金。VEC的有效性已在所研究的合金系统中得到证实。从元素对微观结构的作用的角度来看，Ti有利于化合物的形成，而元素V，Cu，Al或Cr则促进单相固溶体的形成。此外，屈服强度达到2730 MPa，CoFeNiTiV合金的极限抗压强度高达3890 MPa，这是迄今为止所有基于CoFeNiTi的HEA中最高的，甚至是所有3d TM HEA。同时，它具有21.3％的良好延展性。CoFeNiTiV合金的这种优异的强度-延展性协同作用可能源于bcc相的主要成分，固溶强化，主要元素之间的牢固键合以及由于溶质的均匀分布而导致的裂纹形核的形成。