Materials removal mechanism in high-speed grinding of particulate reinforced titanium matrix composites

A finite element (FE) model was established for high-speed grinding of particulate reinforced titanium matrix composites (PTMCs). The materials removal mechanism, including the grinding force and resultant stress, the removal behavior of alloy matrix and reinforcing particles, have been analyzed. Particularly, the effect of grinding parameters on the surface defects was discussed. The results indicate that, the grinding force has different characteristics when the alloy matrix and reinforcing particle were removed, respectively, and the grinding force fluctuates significantly in the removal process of reinforcing particle. The material removal can be divided into four stages: plastic removal of the alloy matrix, crack initiation in reinforced particles, crack propagation in reinforced particles, brittle failure of reinforced particles. Under the current grinding conditions, compared with the grinding speed, the undeformed chip thickness has greater influence on the formation of machined surface defects. The simulation results agreed well with experiment.