三维织物增强铝基复合材料具有高比强度、高比模量以及优良的耐高温和抗冲击性能，是制造航空航天耐热结构的理想材料，目前尚缺乏其高温环境下力学特性与失效机制的系统性研究。本工作研究了高温(400 ℃)环境下斜纹碳布缝合织物结构增强铝基复合材料的准静态拉伸力学行为与失效机理，并根据其织物结构和纱线微观组织特征建立了基于微观和细观尺度代表性单胞的细观力学有限元模型；采用数值模拟与实验结合的方法分析了复合材料在高温拉伸过程中的宏观力学响应、组元结构损伤演化与渐进失效行为。结果表明，复合材料的高温拉伸模量、强度与断裂应变的实验均值分别为103.20 GPa、621.60 MPa和0.819%，数值模拟得到拉伸应力-应变曲线与复合材料高温拉伸实验曲线总体上吻合较好。高温环境下复合材料内部存在复杂的热应力，基体合金和纱线分别处于压应力和拉应力状态。在拉伸初期阶段，复合材料中缝合纱失效、经/纬纱搭接处基体损伤和经纱局部失效，但表现出了线弹性力学响应。随着拉伸载荷增大，基体的损伤程度加重且沿织物斜纹方向出现严重的基体损伤区和纬纱开裂区，导致随应变增加拉伸应力的增长速率减缓。拉伸变形后期产生显著且互相重叠的基体和纱线失效带，经纱的轴向断裂使得复合材料失去承载能力并且拉伸应力急剧下降。高温拉伸断口中缝合纱和纬纱的断口较为平整，而经纱的断裂拔出长度不一，且呈现大量纤维断裂拔出并伴随基体合金撕裂的微观形貌特征。

Three-dimensional fabric-reinforced aluminum matrix composites with high specific strength and modulus, excellent high-temperature resistance, and impact resistance are ideal structural materials for fabricating heat-resistant components in aeronautics and aerospace engineering. However, few studies have explored the mechanical properties and fracture behaviors of these composites in high-temperature environments. This study aims to investigate the quasi-static tensile behaviors and failure mechanisms of a stitched twill carbon fabric-reinforced aluminum matrix composite at an elevated temperature of 400 ^oC. Based on the fabric structure and yarn microstructure, a mesoscle finite element model was established using representative unit cells at the microsale and mesoscale. The macroscopic mechanical response, damage evolution, and failure mechanism of the composite during the tensile test at an elevated temperature (400 ^oC) were analyzed through numerical simulations and experiments. Results show that the tested tensile modulus, strength, and fracture strain at 400 ^oC are 103.20 GPa, 621.60 MPa, and 0.819%, respectively. The calculated tensile stress-strain curve aligns with the experimental curves obtained from high-temperature tensile tests. The composites experience complex thermal stress at elevated temperatures, with the matrix pocket under compressive stress and the yarn structure under tensile stress. In the initial tensile stage, the matrix between interlaced weft/warp yarns is damaged, and local failure zones appear in the stitch and warp yarns; however, the composite exhibits a linear elastic response. As the tensile load increases, the degree of damage in the matrix pocket gradually increases, leading to the emergence of serious matrix damage zones and weft yarn cracking along the twill direction of the fabric. Consequently, the growth rate of tensile stress in the tensile curve declines with increasing tensile strain. In the final stage, the matrix failure zone and yarn fracture zone overlap. The axial fracture of warp yarn, in particular, leads to catastrophic fracture of the composite, resulting in a dramatic drop of the tensile stress. The stitch and weft yarns in the composites exhibit a flat fracture morphology, whereas the fractured warp yarn presents rugged fracture surfaces. A mass of fiber pull-out is observed on the microscopic fracture surface of a warp yarn, accompanied by matrix alloy tearing characteristics.