Mechanical behaviour and microstructural characterization of 3D four-directional braided SiO2f/SiO2 composites

作者：Liu Y; Zhu J^*; Chen Z; Li C; Boafo F E

来源：Fatigue and Fracture of Engineering Materials and Structures, 2012, 35(10): 953-961.

DOI：10.1111/j.1460-2695.2012.01682.x

• fibre-reinforced composite
• fracture mechanics
• microstructure
• mechanical properties

In this paper, SiO2f/SiO2 composites reinforced by 3D four-directional braided quartz preform were prepared by the silica sol-infiltration-sintering method in a relatively low sintering temperature (450 degrees C). To characterize the mechanical properties of the composites, mechanical testing was carried out under various loading conditions, including tensile, flexural and shear loading. The microstructure and the fracture behaviour of the 3D four-directional braided SiO2f/SiO2 composites were studied. The tensile strength, flexural strength and the in-plane shear strength were 30.8 MPa, 64.0 MPa and 22.0 MPa, respectively. The as-fabricated composite exhibited highly nonlinear stressstrain behaviour under all the three types of loading. The tensile and flexural fracture mechanisms were fully discussed. The fracture mode of the 3D four-directional braided SiO2f/SiO2 composite in the Iosipescu shear testing was based on a mixed mechanism because of the multi-directivity of the composite. Owing to low sintered temperature, the fibre/matrix interfacial strength was weak. The SiO2f/SiO2 composites showed non-catastrophic behaviour resulting from extensive fibre pull-out during the failure process.

• 出版日期2012-10
• 单位南京航空航天大学; 中材科技股份有限公司