A micromechanics analysis of the material removal mechanisms in the cutting of ceramic particle reinforced metal matrix composites

摘要

In previous investigations on the cutting of ceramic particle reinforced metal matrix composites using the finite element (FE) method, the particles are usually considered to be rigid. This is inconsistent with the actual situation and thus makes the FE predictions less practical. This paper proposes a micromechanics model to investigate the material removal mechanisms by considering the elasticity and fracture of the particles. It was found that the interaction position of a particle relative to the cutting edge greatly influences the particle and matrix fracture, particle-matrix debonding, surface integrity and cutting forces. There are two particle cracking mechanisms. One is caused by the direct contact of the cutting edge with the particle, and the other is due to the indirect tool-particle interaction through matrix. When the cutting path is below a particle, a smooth surface without subsurface damage can be achieved. When it is passing through a particle, particle fracture mostly occurs. If it is above a particle, subsurface damage is dominated by particle-matrix debonding. Cutting force peaks once the cutting edge is in contact with a particle and the cutting edge is easier to be damaged when the tool is passing through the upper part of the particle.