Machining of metal matrix composite materials (MMC) with diamond based cutting tools

摘要

Metal Matrix Composites (MMC) are a new class of materials that consist of a non-metallic phase distributed in a metallic matrix with properties that are superior to those of the constituents. The principal use for these materials is for light weight high performance component due to their enhanced mechanical properties and low density. Their high thermal conductivity and low thermal expansivity also make them suitable for automotive brake applications. On the other hand MMC's are extremely difficult to machine (turning, milling, drilling, threading), due to their extreme abrasive properties. In fact the commercial available cemented carbides tools coated with titanium nitride (TiN), titanium carbides (TiC) or titanium and aluminium nitride (TiAlN), show high wear rate, making the machining of these materials extremely expensive. With diamond tools (mono crystalline diamond (MCD) or poly crystalline diamond (PCD) the wear rate is low, but the price per tool is very high (at least 5 to 10 times superior to a commercial TiN or TiAlN coated tools) and the choice of commercial available geometry shapes is very limited.