Recent developments include the use of ceramic tools in high-speed machining of superalloys. An important application is machining of nickel-based superalloys, such as Inconel 718 and Incoloy 901. Nickel-based superalloys are widely used for components with high strength at elevated temperatures, which is a typical requirement for the aircraft industry as well as for gas and steam turbines. However, these superalloys are extremely difficult to cut. The main reasons for the poor machinability of the nickel-based superalloys are their high shear strength and rate of work hardening. The poor thermal diffusivity of these alloys also results in heat concentration in the vicinity of the cutting tip, limiting tool life because of the rapid increase in wear.