颗粒增强铝基复合材料因其优异的比强度和比刚度在航空航天和轨道交通等领域应用广泛，但增强相引入导致的脆性断裂及强韧性矛盾问题限制了其进一步发展。传统的准静态表征手段难以实时捕捉材料在载荷作用下动态损伤演化过程。为揭示颗粒增强铝基复合材料的动态断裂机制，解决传统表征手段难以实时捕捉损伤演化的难题，本研究利用上海同步辐射光源BL16U2线站，建立了时间分辨率高达5 Hz的原位动态连续拉伸X射线计算机断层扫描(Computed Tomography, CT)实验方法，实现了对12 vol.% Ti2AlC /Al复合材料的断裂全过程的4D (3D空间+时间)观测。结合深度学习与环境遮挡算法，成功解决了低信噪比动态图像中增强相与微裂纹的精准分割难题。研究发现：(1)损伤萌生具有显著的尺寸依赖性，微裂纹优先在体积较大及团聚的Ti2AlC颗粒内部形核；(2)损伤演化呈现“布式形核—基体桥接—局部化聚合”的三阶段特征；(3)在失效临界点，铝基体发生开裂，从而使孤立的微裂纹快速聚合，导致裂纹数量锐减而主裂纹体积占比激增，最终引发失稳断裂。本研究揭示了MAX相增强铝基复合材料的动态断裂机制，证明了亚秒级高时空分辨CT在捕捉材料非线性失效行为方面的独特优势

Particle-reinforced aluminum matrix composites are widely used in aerospace and rail transportation fields due to their excellent specific strength and specific stiffness. However, their further development is limited by brittle fracture and the strength–toughness trade-off caused by the introduction of reinforcements. Traditional quasi-static characterization methods are inadequate for capturing the dynamic damage evolution of materials under load. To address this challenge and reveal the dynamic fracture mechanisms of Particle-reinforced composites, this study developed an in situ dynamic continuous tensile X-ray computed tomography (CT) method with a temporal resolution of up to 5 Hz at the BL16U2 beamline of the Shanghai Synchrotron Radiation Facility. This approach enabled 4D (3D space and time) observation of the entire fracture process of a 12 vol.% Ti2AlC/Al composite. By combining deep learning and ambient occlusion (AO) algorithms, the challenges associated with accurately segmenting reinforcements and microcracks in low signal-to-noise ratio dynamic images were successfully addressed. The findings revealed that: (1) Damage initiation exhibited significant size dependence, with microcracks preferentially nucleating inside larger and agglomerated Ti2AlC particles; (2) Damage evolution followed a three-stage characteristic of “multiple-site crack initiation–matrix connection–localized coalescence”; (3) At the critical point of failure, isolated microcracks rapidly coalesced by the Al matrix cracks, leading to a sharp decrease in the number of cracks and a drastic increase in the volume proportion of the main crack and ultimately triggering unstable fracture. This study elucidated the dynamic fracture mechanism of 12 vol.% Ti2AlC/Al composite and demonstrated the unique advantages of sub-second high spatiotemporal resolution CT in capturing nonlinear failure behaviors in materials.