为揭示TC4钛合金在循环变形过程中的微观组织演变、位错组态及滑移行为，以探究其变形损伤机制，本工作通过EBSD和TEM等显微分析手段对TC4钛合金展开研究。结果表明，在加载初期，材料快速硬化，微织构区域与周围晶粒的变形不协调导致应变高度集中。随后材料进入准稳态阶段，整体发生塑性累积；受材料织构和加载方向影响，锥面\left\{\mathrm{10}\overline{\mathrm{1}}\mathrm{1}\right\}<c + a>滑移系以最高Schmid因子激活，主导变形并推动晶粒取向逐步向<\mathrm{11}\overline{\mathrm{2}}\mathrm{0}>方向演化；循环变形过程中α/β相界面处位错增殖并在界面处平行堆积，界面作为位错源和障碍区提高了材料寿命。α/β界面处位错演化与微织构区域应变高度集中的协同作用是TC4钛合金循环变形损伤的主要机制。

The cyclic damage behavior of TC4 alloy, which is widely utilized in aerospace and other fields, is critical to the structural integrity of its components. The aim of this study is to elucidate the underlying microstructural damage mechanisms, from the aspect of microstructural evolution, slip activity, and dislocation configurations, during cyclic loading through advanced characterization techniques including EBSD and TEM. The results indicate an initial rapid hardening stage, during which strain is highly localized in microtextured regions due to deformation incompatibility with the surrounding grains. The material subsequently reaches a quasi-steady state, which is marked by accumulated plasticity. Influenced by crystallographic texture and loading direction, the pyramidal \left\{\mathrm{10}\overline{\mathrm{1}}\mathrm{1}\right\}<c + a> slip system exhibits the highest Schmid factor and is preferentially activated, dominating the deformation process and promoting a gradual grain reorientation toward the <\mathrm{11}\overline{\mathrm{2}}\mathrm{0}> direction. TEM analysis indicates that dislocations multiply and align parallel to α/β phase interfaces during cyclic deformation. These interfaces function as both dislocation sources and barriers, thereby enhancing the material's fatigue life. The synergistic coupling between dislocation activity at α/β interfaces and pronounced strain localization within microtextured regions is identified as the dominant mechanism governing cyclic deformation damage in TC4 alloy.