Simulation and experimental investigation on the cutting mechanism and surface generation in machining SiCp/Al MMCs

Abstract

This paper presents the investigation on the cutting mechanism in SiCp/Al turning process. The fracture and removal mechanism of SiC particle and its influence on surface generation are investigated on the basis of a three-dimensional (3D) finite element model. Different depth of cut is adopted in this simulation to study the influence of relative position between the cutting tool and SiC particle on the cutting mechanism. By comparing the topography of the machined surface at different depths of cut, the influence of relative particle position on the surface topography was analysed. The dynamic change process of the stress/strain map was used to reveal the formation mechanism of particle fracture. Different particle behaviours such as slightly fracture at top side, residual fragments embedded within cavity and completely debonding are observed in this model. Various types of defects on the machined surface are also observed such as shallow cavity around embedded particles, severe plastic deformation of matrix materials around cavity due to particle squeezing and cavity caused by particle debonding. In addition, the fragments of particles squeezed by cutting tool during cutting process are found to change the chip formation mechanism. Finally, the simulation results are verified by experimental data from precision turning.