Grinding characteristics and removal mechanism of 2.5D-needled Cf/SiC composites

Abstract

The impacts of the fibre direction and grinding depth on the 2.5D-needled Cf/SiC material surface topography, surface roughness, grinding force and grinding chips were researched in this study. Three basic failure models were built to explain the grinding process, and the machining mechanisms were analysed in detail and discussed based on the indentation fracture mechanics and experimental results. The grinding depth and fibre orientation have a large influence on the surface quality, grinding force and grinding chips. The surface topography, grinding chips and force changed dramatically when the grinding depth was increased from 10 to 50 μm. Similarly, the fibre orientation also affects these evaluation parameters. According to grinding mechanism analysis, changing the fibre orientation also transforms the force model, which contains shearing, extrusion, and tensile forces. Matrix cracks, fibre wear, fibre fracture, interfacial debonding, fibre outcrop and fibre pull-out are the primary removal forms of 2.5D-needled Cf/SiC materials based on the ground surface topography. These characteristics can also be proven by analysing the grinding mechanism. The goal of this paper is to determine the evaluation indicators for 2.5D-needled Cf/SiC materials based on the mechanism conclusions and to provide meaningful recommendations for improving the composite material grinding quality.