依据连续碳化硅纤维增强钛基复合材料在实际制造工艺过程中形成的纤维/基体微观界面结构，该文构建了一种原子尺度的SiC/C/Ti多层界面结构模型。采用分子动力学方法分别计算了热解C/无定形C、TiC/Ti两种类型界面的混合模式断裂能(临界Ⅰ与Ⅱ型能量释放率分别为(7.87 J/m²)/(15.50 J/m²)、(8.71 J/m²)/(12.14 J/m²))，分析了不同加载方式下纤维/基体界面的断裂形式差异，揭示了在拉伸载荷主导条件下，热解C/无定形C界面是纤维增强钛基复合材料的性能薄弱位置。该研究为后续构建纤维增强钛基复合材料的多尺度仿真模型提供了基础。

Objective: Continuous silicon carbide (SiC) fiber-reinforced titanium matrix composites (TMCs) have become critical structural materials in aerospace because of their exceptional specific stiffness and strength. However, their anisotropic mechanical properties and complex interfacial failure modes pose notable challenges for damage prediction and structural reliability. This study addresses the critical knowledge gap regarding the multiscale fracture mechanisms of practical SiC fiber-reinforced TMCs containing hierarchical C/TiC/Ti interfacial architectures formed by hot isostatic pressing (HIP). Existing research predominantly focuses on idealized Ti/TiC systems; the crucial influence of pyrolytic carbon layers with turbostratic structures is neglected. Our work pioneers a comprehensive investigation into the mixed-mode fracture behaviors of carbon-rich (pyrolytic carbon/amorphous carbon) and TiC-dominated interfaces through atomic-scale modeling, providing essential parameters for the optimization of interfacial design against multiaxial failures. Methods: We developed a multiscale simulation framework combining molecular dynamics and interfacial mechanics analysis. Atomic models of SiC/C/Ti multilayer interfaces were constructed to replicate realistic HIP-generated microstructures. For pyrolytic carbon/amorphous carbon interfaces, the analytical bond-order potential (ABOP) was employed to simulate liquid quenching (8 000 K) and annealing (4 000 K). Turbostratic carbon configurations matching chemical vapor deposition (CVD) characteristics were generated. The Ti/TiC interfaces were modeled using the 2-nearest-neighbor modified embedded atom method (2NN-MEAM) potential to capture lattice mismatch (4%) and interdiffusion between α-Ti (0 0 0 1) and TiC (1 1 1) planes. The following two critical loading scenarios were simulated: (1) tensile separation (Mode Ⅰ) with 0.5 Å/ps displacement rate and (2) shear deformation (Mode Ⅱ) at 5 Å/ps sliding velocity. The NVT ensemble with Nose-Hoover thermostat was used to maintain a 300 K operating temperature. Fracture energy release rates were calculated through the J-integral analysis of traction-separation curves. Atomic bond evolution was quantified through polyhedral template matching and common neighbor analysis in OVITO software. Results: The pyrolytic carbon/amorphous carbon interfaces demonstrated distinct anisotropic fracture mechanisms as follows: (1) tensile loading caused the sequential fracturing of graphene-like layers (max traction: 7.36 GPa; Type Ⅰ energy release rate: 7.87 J/m²), and (2) shear deformation induced 45° delamination through interlayer sliding (max shear: 4.53 GPa; Type Ⅱ energy release rate: 15.50 J/m²). By contrast, the Ti/TiC interface exhibited superior tensile strength (12.8 GPa; Type Ⅰ energy release rate: 8.71 J/m²) but unexpected shear-induced failure: (1) shear stress was concentrated at the Ti lattice defects rather than at the interface, and (2) 45° cleavage fracture in Ti matrix (Type Ⅱ energy release rate: 12.14 J/m²) revealed matrix failure. The crack propagation paths fundamentally differed between the interfaces. The pyrolytic carbon interfaces showed self-similar crack growth along weak Van Der Waals gaps, and the Ti/TiC interfaces displayed crystallography-dependent branching along (0 0 0 1) planes. Conclusions: This study establishes the quantitative correlation between HIP-processed interfacial architectures and fracture resistance anisotropy in SiC fiber-reinforced TMCs, bridging atomic-scale mechanisms to macroscopic composite performance. The following three key advances are achieved: (1) identification of pyrolytic carbon interfaces as the tensile weak link (10.6% lower critical energy release rate compared with Ti/TiC interfaces), (2) discovery of shear-induced matrix failure mechanisms through dislocation pileup and shear band formation overriding interfacial strength, and (3) development of process-informed traction-separation laws incorporating HIP temperature for multiscale modeling. The results fundamentally revise the conventional "weak interface" paradigm by demonstrating the load-dependent dominance of different interfacial layers—pyrolytic carbon governs tensile failure, whereas Ti matrix plasticity dictates the shear response. This study provides fundamental data and mechanistic insights for the subsequent development of multiscale simulation models for predicting spontaneous crack initiation in fiber-reinforced Ti matrix composites and addresses interfacial delamination under combined thermomechanical loading in aeroengine components.