Ti-Nb二元合金具有形状记忆效应、抗腐蚀性、无毒性、超导电性等特点，在航空航天、医疗、超导领域得到 了广泛应用。 通过真空自耗电弧熔炼和热轧加工制备了Nb含量35%~55%(质量分数)的Ti-Nb合金，分析了Nb 含量对合金微观组织演变及力学行为的影响及作用机制。 结果表明，当Nb含量为35%时，其固溶态显微组织由 直径约50~100 μm 的等轴晶组成，晶粒内部存在应力诱导马氏体，拉伸曲线呈现出明显的双屈服现象，抗拉强度 可达650MPa，但屈服强度仅为225MPa。 随着Nb含量增加至45%~55%，合金晶粒细化且β相稳定性增强，抑制了马 氏体相变，拉伸曲线无明显双屈服现象，实现了强度与塑性的良好匹配。Nb元素通过β相稳定化、固溶强化及晶粒细化 三重作用机制，显著改善了合金的综合力学性能。

Ti-Nb alloys are widely used in aerospace, medical, and superconductivity applications because of their excellent properties, such as shape memory effects, corrosion resistance, nontoxicity, and superconductivity. Ti-Nb alloys with compositions ranging from 35 wt.% to 55 wt.% were prepared via vacuum arc remelting and hot rolling processing to elucidate the influence of the Nb content on the microstructural evolution and mechanical behavior. The results demonstrate that the microstructure of the solution-treated Ti-35Nb alloy consists of equiaxed grains with a grain size of approximately 50~100 μm, accompanied by stress-induced martensite within the grains. The tensile curve exhibits a distinct double-yield phenomenon, with an ultimate tensile strength of 650 MPa but a relatively low yield strength of 225 MPa. As the Nb content increases to 45 wt.%~55 wt.%, the alloy undergoes significant grain refinement, coupled with enhanced β-phase stability, which suppresses martensitic transformation. Consequently, the tensile curves display no double-yield behavior, and the strength and ductility of the alloy match well. The incorporation of Nb improves the comprehensive mechanical performance through three mechanisms: β-phase stabilization, solid-solution strengthening, and grain refinement.