Diamond turning and grinding of aluminum-based metal matrix composites

This paper reports research results obtained from diamond turning and grinding of aluminum-based MMCs reinforced with either SiC or Al2O3 particles. Both polycrystal diamond (PCD) and single crystal diamond (SCD) tools were used for turning the MMCs at depths of cut ranging from 0 to 1.6 mum. Diamond grinding wheels were used to grind the MMCs at depths of cut from 0.1 to 1 mum. Besides the depth of cut, ductile-mode turning of the reinforcing particles might also be affected by the orientation of the particles. Grinding using a 3,000-grit diamond wheel at depths of cut of 1 and 0.5 mum produced ductile streaks on the Al2O3 particles and the SiC particles, respectively. There was almost no subsurface damage except rare cracked particles. At the same depth of cut, the surfaces ground with the diamond grinding wheel revealed more ductile streaks on the reinforcement ceramic particles than those obtained from SCD turning.