Dynamic compressive fracture of C/SiC composites at different temperatures: Microstructure and mechanism
Dynamic compressive fracture of C/SiC composites at different temperatures: Microstructure and mechanism
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不同温度下C/SiC复合材料的动态压缩断裂：微观结构与机理
DOI：
10.1016/j.ijimpeng.2017.08.001
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发表时间：
2017-11-01
影响因子：
5.1
通讯作者：
Li, Yulong
中科院分区：
文献类型：
--
作者：
Li, Tao;Duan, Yu;Li, Yulong
从实验和数值两方面研究了C/SiC复合材料在压缩载荷作用下的断裂行为。使用改进的分离式霍普金森压杆(SHPB)和高速摄影进行了动态实验。采用基于微观结构的方法对碳化硅复合材料进行了模拟，包括碳化硅基体、空洞、经纬纤维束等。数值模拟准确地捕捉到了材料的微观结构动态响应和微损伤演化过程。准静态载荷下的C/SiC复合材料断口比较粗糙，有纤维束分裂和纤维拔出。然而，在动态载荷下，断裂面变得更加平坦，纤维束分裂或纤维拔出可以忽略不计。在高速图像上观察到了两种动态断裂模式，数值模拟结果证实了这两种动态断裂模式是由非均匀组织引起的。其中一种断裂方式显著提高了C/SiC复合材料的韧性(提高了35%)，但强度基本没有降低。此外，低温热处理显著影响了C/SiC复合材料的力学性能(如弹性模量、强度和断裂应变)，这是由于微裂纹数量的增加和纤维-基体界面强度的降低所致。(C)2017爱思唯尔有限公司。保留所有权利。
Fracture behavior of C/SiC composites under compressive loading is investigated both experimentally and numerically. Dynamic experiments are carried out using a modified split Hopkinson pressure bar (SHPB), along with high-speed photography. A microstructure based approach is employed to model the C/SiC composites, including SiC matrix, voids, warp and weft fiber bundles. Dynamic microstructure response and microdamage evolution are captured accurately by numerical simulations. The fracture plane of the C/SiC composites under quasi-static loading is rough, with fiber bundle splitting and fiber pullout. However, the fracture plane becomes much smoother under dynamic loading, with a negligible fiber bundle splitting or fiber pullout. Two dynamic fracture modes are observed in the high-speed images, and proved to be induced by the inhomogeneous microstructure according to the numerical simulation results. One of the fracture modes improves the toughness of the C/SiC composites significantly (an increase of 35%), mostly without strength decrease. Moreover, the low-temperature heat treatment significantly influences the mechanical properties (e.g. elastic modulus, strength, and fracture strain) of the C/SiC composites, owing to the increase in the number of microcracks and the decrease in the strength of fiber-matrix interfaces. (C) 2017 Elsevier Ltd. All rights reserved.