三维角联锁机织铝基复合材料面内拉伸力学行为与失效机制

Mechanical behavior and failure mechanism of the 3D angle interlocking woven reinforced aluminum matrix composites under in-plane tensile loading

针对真空压力浸渗法制备的三维角联锁机织铝基复合材料,采用细观力学有限元模拟与试验结合的方法研究了其面内拉伸变形损伤与断裂力学行为。结果表明:复合材料拉伸应力-应变曲线的计算与试验结果吻合较好,经(纬)向拉伸初始弹性模量、极限强度和断裂应变的计算误差分别为3.96%(1.11%)、1.40%(6.86%)和-5.49%(3.73%);经向拉伸载荷作用下,经纱界面及其邻近基体合金先后发生损伤,随拉伸应变增加损伤累积和交互作用依次引发界面、基体和纬纱失效,变形后期经纱的断裂最终导致复合材料经向拉伸失效;纬向拉伸变形前期,经纱界面和经纬纱之间薄弱的基体合金相继产生损伤和失效现象,经纱在变形中期即出现横向破坏,起主要承载作用的纬纱轴向断裂是纬向拉伸的主要失效机制,由于三维角联锁机织体中纬纱体分远低于经纱,复合材料纬向拉伸模量和强度分别仅为经向的81.8%和56.5%。

3D angle interlocking fabric reinforced aluminum composites were prepared by the vacuum assisted pressure infiltration method. The mechanical properties and damage behavior of the composites subjected to inplane tensile loading were investigated using the micromechanical finite element simulation and experimental method. The results show that the tensile stress-strain curve from simulation is in agreement with the testing curves, where the calculation errors of the initial modulus, ultimate strength and fracture strain in warp(weft) direction are 3.96%(1.11%), 1.40%(6.86%) and-5.49%(3.73%), respectively. Under the warp directional tension condition, the interface on warp yarns and the adjoint matrix alloy damage successively. With the increase of tensile strain, these damage zones accumulate and interact with each other, leading to the failure of interface, matrix and weft yarns in sequence. The fracture of warp yarns in the terminate stage induces the ultimate failure of the composites. During the weft directional tensile process, the interface on warp yarns and the thin matrix alloy between yarns damage and fail firstly. The transverse fracture of warp yarns occurs in the middle stage of tensile deformation. The axial fracture of weft yarns, which sustain the loading stress at the end of deformation process, is the main failure mechanism of the composites under weft directional tensile condition. The tensile modulus and strength in weft direction are 81.8% and 56.5% times than those in warp direction, owing to the lower volume fraction of weft yarns in the 3D angle interlocking fabric.