增材制件内部特有的缺陷会导致高端复杂金属构件在不同服役载荷、环境下的损伤演变特性不同，传统无损检测技术无法对材料内部微观结构的变化进行实时动态表征。而同步辐射X射线断层扫描技术具有穿透性强、时空分辨率高、三维可视化等特点，在增材制件缺陷的原位、动态、无损表征方面具有独特优势。对同步辐射X射线断层扫描原理与特点进行分析，以增材制造钛合金为例，简要介绍了其对材料内部缺陷尺寸、形貌及分布特征，分析了缺陷致疲劳损伤行为的原位观测，以及其在基于三维成像数据的含真实缺陷结构特征的有限元仿真等研究中的典型应用，展望了基于高能同步辐射光源的X射线三维成像技术在增材制造金属材料领域的广阔应用前景。

Metal additive manufacturing (AM) technology is widely used in aerospace and other advanced industrial fields due to the unique advantage in the rapid forming of complex metal components. However, the defects induced damage behaviors of the AM parts under different service loads and environments are different. Traditional non-destructive testing technology can not dynamically characterize the evolutions of the internal microstructure of materials in real time, while synchrotron radiation X-ray tomography (SR-CT) has many advantages in it, such as strong penetration, high spatial and three-dimensional visualization, etc. Based on the analysis of the principle and characteristics of SR-CT and taking the AM titanium alloy as an example, some typical applications of SR-CT are briefly introduced, such as the quantitative analysis of the size, morphology and distribution characteristics of defects in AM parts, the in-situ observation of defects induced fatigue damage, and the finite element simulation analysis based on three-dimensional imaging data. The broad application prospects of SR-CT based on High Energy Photo Source (HEPS) in the field of AM metal materials are prospected.