Mechanical properties and microstructure of 2.5D (shallow bend-joint) quartzf/silica composites by silicasol-infiltration-sintering

• Main Authors: Liu Yong, Zhu Jianxun, Chen Zhaofeng, Jiang Yun, Li Binbin, Chen Zhaohai, Lin Long, Guan Tianru, Li Chengdong
• Format: Article
• Language: English
• Published: De Gruyter 2012-03-01
• Series: Science and Engineering of Composite Materials
• Subjects: fracture mechanism; interface; mechanical properties; microstructure; 2.5d quartzf/silica composites
• Online Access: https://doi.org/10.1515/secm.2011.0061
• ISSN: 0792-1233; 2191-0359

Silica composites (2.5D quartz fibers-reinforced) were prepared by the silicasol-infiltration-sintering method. The fiber volume fraction was 50.5%. The composites were sintered in a temperature range of 400∼450°C. Mechanical properties of the composites were determined by pc-controlled electronic universal testing machines. The microstructure of the composite was observed by scanning electron microscopy (SEM). The density of the composite was 1.77 g/cm3. The flexural strength and the shear strength of the composites were 50.35 MPa and 22.41 MPa, respectively. The stress-deflection curves exhibited mostly nonlinear behavior; the failure was not catastrophic. Some fibers pull-out indicated that the composite had part toughness. However, abundant fibers fractured in the same plane revealed that the composite presented serious brittleness. The fracture mechanism of the composite was a mixture of ductile and brittle modes.