Theoretical and experimental studies of the ductile mode of cutting brittle materials (semicon ductors, ceramics, and glass) have been considered. The ductile mode of cutting has been based on the implementation of high pressure induced phase transformations in a material machined that followed by a cutting of a transformed amorphous layer, which makes it possible to avoid cracking. Publications on studies of phase transitions in brittle materials in the course of the indentation, scratching, friction, and cutting have been reviewed. It has been shown that the cutting depth, cutting edge radius of a tool, chip thickness, tool cutting edge inclination, and crystallographic orientation of a material machined and dia mond tool as well as a type of lubricoolant are the decisive factors in implementing the ductile mode of cutting. KOVALCHENKO 1 2 Cutting length 3 4 Resistance force, N Fig. 3. Scheme of different modes of removing a brittle material with increasing normal load and cutting depth [42]: elastic (1) and elastoplastic (2) deformations, plastic (3) and brittle (4) removal of the material.