Removal mechanism of unidirectional Cf/SiC composites based on single diamond grit scratching

Abstract

To investigate the scratch removal mechanism of unidirectional Cf/SiC composite materials, quasi-static scratching tests were carried out using a single diamond abrasive grain to analyze the changes in acoustic emission signals of the scratched materials under different indentation loads. These tests were complemented by SEM images to analyze the removal behavior and scratch removal mechanism of the materials. The test results show that the acoustic emission signal value increases with the increase in indentation load. Under the same parameters, the signal value in the SB direction is larger, and the signal fluctuation is more severe. Combining the acoustic emission signal and SEM morphology analysis, it is concluded that the scratch removal behavior of the material varies in different directions. The material primarily undergoes brittle removal. In the SA direction, fibers mainly experience tensile fracture and fiber pull-out, whereas in the SB direction, the main fracture modes of the fiber are bending fracture and shear fracture. According to the SEM morphology analysis, the formation process of the removal behavior and the material scratch removal mechanism are described.

Keywords

• unidirectional cf/sic composites
• single diamond grit scratching
• acoustic emission signal
• material removal mechanism