利用扫描电镜等分析手段对Ｂ／Ａｌ复合材料疲劳断裂的特征及机理进行了分析研究。结果表明，随着应力水平的提高，Ｂ／Ａｌ复合材料的疲劳断口由拔出型趋向于平断型，其断裂机理也有所不同。在同一应力水平下，界面结合较强的试样具有较高的断裂周次。此外，分析结果还表明，纤维在基体中过于密集的或分层的排列，将导致复合材料中纤维的损伤或材料性能的下降。 The characteristics and mechanism of fatigue fracture of B / Al composites were analyzed by SEM and other analytical methods. The results show that with the increase of stress level, the fatigue fracture of B / Al composites tends to be flat and the fracture mechanism is different. At the same stress level, the stronger interfacial bonding specimens have higher fracture cycles. In addition, the analysis also shows that the fibers are too dense or stratified arrangement in the matrix, resulting in fiber damage or material properties degradation in the composite.