Abstract: The fracture experiments of AP/Al/CMDB propellant are researched using a constant speed tension under 2 mm/min stretching rate. The CCD optical microscope is used to monitor the process of the initial fracture and propagating. The damage evolution mechanism of the material near crack tip is elaborated. Scanning electron microscope is applied to characterize the fracture morphology of the propellant. Moreover，the large particle size ammonium perchlorates (AP) microstructure evolution mechanism is also analyzed in detail. The?fracture?energy is obtained by the method of numerical integration. Results show that a typical damage phenomenon is found in the process of crack tip and the propagation path. The AP particles de-wetting behavior dominates the process of the micro holes and micro crack initiation，nucleation，growth，merging，which characterize the propellant fracture mechanism and controlls the nonlinear fracture characteristics of the propellant. The fracture energy obtained by the numerical integral method is 1.765±0.025N/mm under 2mm/min stretching rate.

Key words: Solid propellant；Damage；De-wetting；Fracture energy

摘要： 开展了关于AP/Al/CMDB推进剂在2mm/min拉伸速率下的断裂实验研究，利用CCD光学显微镜实时监测了裂纹的起裂与扩展过程，并阐述了裂尖材料的损伤演化机理；结合电镜扫描(SEM)技术对推进剂的断面形貌进行了表征，分析了大粒径高氯酸铵(AP)的微观结构演化机理；采用积分法获得推进剂的断裂能。结果表明:推进剂在起裂与扩展过程中裂尖区域材料存在明显的损伤现象，AP颗粒的脱湿行为主导着微孔洞和微裂纹的萌生、成核、长大、合并过程，表征着推进剂的断裂机理，并控制着推进剂的非线性断裂特性；采用积分法获得推进剂在2mm/min拉伸速率下的断裂能为1.765±0.025N/mm。

关键词: 固体推进剂；损伤；脱湿；断裂能