基于兵器领域对轻质抗冲击材料的现实需求，以具备高强度-塑性-冲击韧性匹配的Ti575合金为研究对 象，通过热处理在Ti575合金中调控出三态组织和魏氏组织，并利用霍普金森压杆技术在3500s-1应变速率下开展动态 力学性能测试，结合扫描电子显微镜对微观组织演化进行分析，揭示Ti575合金在高应变速率下的变形行为和响应机 制，从而为后续研究提供指导意义。研究结果表明，Ti575合金不同组织状态下的高应变速率变形行为均分为弹性阶段、 应变硬化阶段、稳定软化阶段和不稳定软化阶段4个阶段。 动态压缩结果表明，三态组织冲击吸收功高于魏氏组织(三 态组织：228J/cm3；魏氏组织：200J/cm3)，呈现出优于魏氏组织的动态力学性能。此外，经高应变速率变形后，两种组织均 呈现绝热剪切失效特征。 三态组织较魏氏组织而言，绝热剪切带数量少、宽度大，表明三态组织具有低于魏氏组织的绝 热剪切敏感性，而三态组织较低的绝热剪切敏感性是其动态力学性能优于魏氏组织的主要原因。 进一步断裂机制研究 表明，不同组织Ti575合金经高应变速率变形后的断口形貌均由韧窝区和平滑区组成，高倍SEM观察表明两种组织均 以韧性断裂机制为主，同时存在典型的剪切断裂特征。

On the basis of the realistic demand for lightweight impact-resistant materials in weaponry, a Ti575 alloy, which possesses high strength-plasticity-impact toughness matching, was taken as the object of this research. Ti575 alloys with trimodal and widmanstätten microstructures were prepared through heat treatment, and dynamic mechanical property tests were carried out at a strain rate of 3 500 s-1 via the Hopkinson pressure bar technique combined with microstructural evolution analysis by scanning electron microscopy observations. This study aims to reveal the deformation behavior and response mechanisms of Ti575 alloys through these tests, thereby providing guidance for subsequent research. The results indicate that the high strain rate deformation behavior of the Ti575 alloy with these two different microstructures can be divided into four stages: the elastic stage, strain hardening stage, stable softening stage, and unstable softening stage. The results of the dynamic compression tests reveal that the trimodal microstructure results in greater impact absorption energy than does the widmanstätten microstructure (trimodal microstructure: 228 J/cm3; widmanstätten microstructure: 200 J/cm3), demonstrating better dynamic mechanical properties of the trimodal structure than that of the widmanstätten microstructure. Additionally, both microstructures display characteristics of adiabatic shear failure during high strain rate deformation. The characteristics of fewer and wider adiabatic shear bands in the trimodal microstructure suggest that it has lower sensitivity to adiabatic shear than the widmanstätten microstructure does, resulting in superior dynamic mechanical properties in the trimodal microstructure relative to the widmanstätten microstructure. Subsequent studies on the fracture mechanisms show that the fracture surfaces of the two microstructures of Ti575 alloys deformed at high strain rates consist of ductile dimple regions and smooth areas. Moreover, high-magnification SEM observations indicate that both microstructures primarily demonstrate ductile fracture characteristics, along with typical signs of shear fracture.