The effect of titanium-alloying on microstructure and mechanical properties of Fe35Ni35Cr20Mn10 high-entropy alloy (HEA) was studied. The microstructure was characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The mechanical properties were examined by tensile and hardness tests. After the homogenization treatment at 1000 °C for 12 h, a great amount of thick/thin η flakes are observed to form at the grain boundaries, regularly intersect-arraying with specific directions that form η-locks. It is found that both the thick and thin η-Ni₃Ti flakes are well coherent with face-centered cubic (FCC) matrix. Ti-alloying makes the homogenized Fe35Ni35Cr20Mn10 HEA possess high yield strength (331 MPa) and excellent ductility (47.2% in elongation), exhibiting a better strength-ductility. The remarkable rise in yield strength is from fine grain strengthening, dislocation hardening and second phase strengthening that are induced by Ti alloying. The refinement of grains induced by Ti alloying, the formation of a number of clear dislocation cells in FCC matrix and many stacking faults in FCC matrix and inside η flakes during the tensile deformation, and especially the coordinated deformation between η flakes and matrix, are thought to be responsible for the excellent ductility. The excellent strength-ductility in homogenized (Fe35Ni35Cr20Mn10)_95.3Ti_4.7 HEA is, more importantly, due to the formation of regular intersect-arraying of η flakes (η-locks) with specific directions. The thick/thin η flakes are all along keeping the coherent relationship with FCC matrix during the total tensile deformation and hence can coordinately deform with the matrix.

研究了钛合金化对Fe35Ni35Cr20Mn10高熵合金（HEA）组织和力学性能的影响。通过X射线衍射、扫描电子显微镜和透射电子显微镜对微观结构进行了表征。通过拉伸和硬度测试检查机械性能。在1000°C均匀化处理12小时后，观察到大量的厚/薄η薄片在晶界处形成，与形成η锁的特定方向规则地相交排列。发现厚η-Ni 3 和薄η-Ni ₃Ti 薄片与面心立方 (FCC) 矩阵很好地结合。Ti合金化使均质化的Fe35Ni35Cr20Mn10 HEA具有较高的屈服强度（331 MPa）和优良的延展性（47.2%的伸长率），表现出更好的强度-延展性。屈服强度的显着提高来自于 Ti 合金化引起的细晶强化、位错强化和第二相强化。认为Ti合金化引起晶粒细化，在拉伸变形过程中，FCC基体中形成大量清晰的位错胞，FCC基体和η片内部产生大量堆垛层错，尤其是η片与基体的协调变形。对优良的延展性负责。均质化（Fe35Ni35Cr20Mn10）_95.3 Ti中优异的强度-延展性_4.7 HEA 更重要的是，由于形成了具有特定方向的 η 薄片（η 锁）的规则相交排列。厚/薄的η薄片在总拉伸变形过程中一直保持与FCC基体的共格关系，因此可以与基体协调变形。