针对粉末冶金法制备的短碳纤维增强铜复合材料(CSf/Cu),采用有限元方法建立细观力学模型,研究材料的拉伸损伤演化和断裂力学行为,并分析弱界面对复合材料拉伸性能的影响。结果表明,CSf/Cu复合材料的拉伸过程可分为弹性阶段、塑性硬化阶段、起始损伤阶段和损伤演化阶段。纤维端部的应力集中造成端部界面脱黏、轴向界面的损伤演化以及纤维桥联,基体损伤及其伴随的界面损伤造成基体破坏是材料断裂的主要机制。碳纤维长度大于60 μm时,纤维的轴向应力分布呈现“w”形,纤维有较强的承载能力;纤维长度为20 μm时,纤维几乎没有承载能力。纤维承受载荷越高,越容易造成界面破坏,随纤维长度从20 μm增加到140 μm,Csf/Cu复合材料的抗拉强度从146 MPa下降到102 MPa。
For the short carbon fiber reinforced copper matrix composites (CSf/Cu) prepared by powder metallurgy, a model was established to analyze the tensile damage evolution, fracture mechanical behavior and the influence of weak interface on mechanical properties of composites. The results show that the composites can be divided into elastic stage, plastic hardening stage, damage initiation stage, and damage evolution stage. The stress concentration at the fiber end causes the debonding of the end interface, the damage evolution of the axial interface and the fiber bridging. The damage of the matrix and the accompanying interface are the main fracture mechanism of the material. When the fiber length is greater than 60 μm, the axial stress of the fiber presents a “w” shape, and the fiber has a strong bearing capacity. When the fiber length is 20 μm, the fiber has almost no bearing capacity. The higher the load on the fiber, the easier it is to cause interfacial damage. With increasing fiber length from 20 μm to 140 μm, the strength of the composite decreases from 146 MPa to 102 MPa.
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