2.5维织物C_f/Al复合材料制备及其经纬向拉伸变形力学行为研究

以石墨纤维2.5维机织物为增强体,铝合金ZL301为基体材料,采用真空辅助压力浸渗法制备了2.5维织物Cf/Al复合材料,研究了3种织物预热温度下制备的复合材料相对致密度和微观组织形貌,分析了其界面产物组成与界面结构特征,测试了其经、纬向准静态拉伸变形力学行为并分析了其断口形貌。结果表明:复合材料织物的细观结构完整,内部纤维分布均匀,致密度随预热温度提高而略有上升,界面棒状产物为Al4C3相,其相对含量随预热温度的提高而增加,从而引起复合材料经向和纬向力学性能的下降。复合材料经向拉伸强度高于纬向拉伸强度,且其应力-应变行为呈现出显著的非线性特征,复合材料经向和纬向拉伸变形过程均可划分为3个阶段:初始弹性变形阶段、中间弹塑性变形阶段和最终损伤与断裂阶段。

Research on the preparation of 2.5D woven fabric Cf/Al composite and its tensile deformation behavior in warp /weft direction

2.5D woven fabric Cf/Al composites with 2.5D graphite fiber fabric as reinforcement and ZL301 as matrix alloy was fabricated by the vacuum pressure infiltration method. The density and microstructure of the composites, which were prepared with three fabric temperature level, was investigated. The crystal structure and composition of the interfacial product was revealed. The quasi-static tensile test and electron fractography was carried out to analyze the mechanical behavior of the composite along the warp and weft direction. The results indicated that the fabric structure can be maintained well, in which the fibers distributed in matrix alloy uniformly. With the increase of fabric temperature, the density of the composites was improved slightly while the relative amount of interfacial product, which was identified to be Al4C3 phase with rod shape, increased obviously, which lead to the reduction of mechanical properties both in warp and weft direction. The tensile strength in warp direction has been proven to be higher than that in weft direction. The stress-strain behavior in warp direction exhibit an significant nonlinear characteristic. The tensile deformation process both in warp and weft direction can be divided into three stages, i.e. the initial elastic deformation segment, the middle elastoplastic deformation segment and the final damage and fracture segment.