叠层穿刺CF/Al复合材料准静态拉伸力学行为与失效机制

针对新型的叠层穿刺碳纤维织物增强铝基复合材料（CF/Al复合材料），通过细观力学数值模拟与实验结合的方法研究了其在准静态拉伸载荷作用下的渐进损伤与断裂力学行为。复合材料经向拉伸弹性模量、极限强度与断裂应变的实验结果分别为129.61 GPa、630.14 MPa和0.75%，细观力学模型预测误差分别为-9.41%、7.57%和1.33%，均匀化计算的宏观应力-应变曲线与实验曲线总体上相符。经向拉伸变形初期首先出现经/纬纱交织处基体合金的局部损伤，随着拉伸应变量的增大依次发生纬纱和穿刺纱的横向开裂，拉伸变形后期基体合金与经纱失效引起宏观应力-应变曲线的急剧下降，复合材料拉伸断口表现为经纱轴向断裂及纬纱和穿刺纱横向开裂共存的形貌特征，纤维拔出和基体断裂导致的经纱轴向断裂是诱发复合材料最终失效的主要机制。

Quasi-static tensile behavior and failure mechanism of laminated puncture CF/Al composites

A novel aluminum matrix composite reinforced with laminated puncture carbon fiber fabric (CF/Al composites) was prepared. The progressive damage and mechanical behavior of the composite subjected to quasi-static tensile loading were investigated by using test and micromechanical simulation method. The test results show that the tensile modulus, ultimate strength and fracture strain are 129.61 GPa, 630.14 MPa, and 0.75%, respectively, and the calculation errors of the above property parameters are -9.41%, 7.57% and 1.33%, respectively. The macroscopic stress-strain curve from the micromechanical simulation agrees well with the test result. At the initial tensile stage, local damages were found in the matrix alloy located between the warp and weft yarns. With the increase of tensile strain, these damage zones accumulated gradually and led to the transverse cracking of weft yarns and piercing yarns in sequence. Thereafter, the warp yarns and matrix alloy failed successively, leading to dramatical dropping of the macroscopic stress-strain curve at the final tensile stage. The tensile fracture morphology was characterized by coexistence of fracture of warp yarns and transverse cracking of weft and piercing yarns. The axial fracture of warp yarns, which was induced by fiber pulling-out and matrix tearing, was the dominant failure mechanism of the composites under the condition of warp-directional tensile loading.