Objective: Tool wear and the mechanisms were investigated when high-speed milling SiCp/2009Al composites. Method: Milling tests were performed using PCD tools in the cutting speed range of 600-1200m/min. The scanning electron microscope (SEM) was used to examine the machined surfaces and tool wear land. XRD was used to analyze the substances on the machined surface and Laser Raman and EDS were used to analyze the elements on the tool wear land. Result: The results show that tool grain breaking-off

abrasive wear

chipping and peeling were the prevalent wear patterns. When milling the high volume fraction material or the heat treated material

or milling with higher cutting speed

micro-cracks will form on the PCD tools. Volume fraction

average size of SiC particles

tool grain size

coolant and heat-treatment have significant influence on the tool wear. Conclusion: The tool life of PCD tools was in the range of 70-240min. The very high-frequency impact and scrape of SiC particles were the main mechanisms for the above wear patterns. The micro-cracks were produced on the tool flank under the combined effects of SiC particle impact

cutting vibration and heat impact. The aluminum and copper had diffused into the tool matrix under the very high cutting temperature and cutting forces. Trivial graphitization had taken place on the PCD tools due to the catalysis of copper in the aluminum matrix.