Liu Yufeng, Li Longbiao, Zhang Zhongwei, Xiong Xiang
Science and Technology of Advanced Functional Composite Materials Laboratory, Aerospace Research Institute of Materials & Processing Technology, Beijing 100076, China.
Powder Metallurgy Research Institute, Central South University, Changsha 410083, China;
Materials (Basel). 2020 Dec 24;14(1):57. doi: 10.3390/ma14010057.
In this paper, monotonic and cyclic loading/unloading tensile behavior of four different 3D needle-punched C/SiC composites are investigated. Under tensile loading, multiple micro parameters of tensile tangent modulus, tensile strength, and fracture strain are used to characterize tensile damage and fracture behavior. Under cyclic loading/unloading, multiple damage micro parameters of unloading residual strain, tensile peak strain, hysteresis loops width, hysteresis loops area, unloading and reloading inverse tangent modulus (ITM) are used to describe the tensile damage evolution. After tensile fracture, fracture surfaces were observed under a scanning electron microscope (SEM). Damage of matrix cracking, interface debonding, fibers fracture and pullout in different plies is observed. Relationships between composite tensile mechanical behavior, damage parameters, and micro damage mechanisms are established. When the fiber volume fraction along the loading direction increases, the composite initial tangent modulus, tensile strength and fracture strain increase, and the unloading residual strain, peak strain, hysteresis width and hysteresis area decrease. For Types 1-4 3D needle-punched C/SiC composite, the fiber volume lies in the range of 25.6-32.8%, the composite initial tangent modulus was in the range of 161.4-220.4 GPa, the composite tensile strength was in the range of 64.4-112.3 MPa, and the composite fracture strain was in the range of 0.16-0.25%.
本文研究了四种不同的三维针刺C/SiC复合材料的单调和循环加载/卸载拉伸行为。在拉伸加载下，使用拉伸切线模量、拉伸强度和断裂应变等多个微观参数来表征拉伸损伤和断裂行为。在循环加载/卸载下，使用卸载残余应变、拉伸峰值应变、滞后回线宽度、滞后回线面积、卸载和再加载反正切模量（ITM）等多个损伤微观参数来描述拉伸损伤演化。拉伸断裂后，在扫描电子显微镜（SEM）下观察断口表面。观察到不同层中基体开裂、界面脱粘、纤维断裂和拔出等损伤情况。建立了复合材料拉伸力学行为、损伤参数和微观损伤机制之间的关系。当沿加载方向的纤维体积分数增加时，复合材料的初始切线模量、拉伸强度和断裂应变增加，而卸载残余应变、峰值应变、滞后宽度和滞后面积减小。对于1-4型三维针刺C/SiC复合材料，纤维体积在25.6-32.8%范围内，复合材料初始切线模量在161.4-220.4 GPa范围内，复合材料拉伸强度在64.4-112.3 MPa范围内，复合材料断裂应变在0.16-0.25%范围内。
