Embrittlement of a high-ductility metal in high-speed machining.

[Display omitted] • Chips produced in cutting of pure iron turns into grains at cutting speed 8000 m/min. • Above 8000 m/min chips are formed by transgranular and intergranular fractures. • High ductile metals can be fabricated brittlely with a high deformation rate. Many materials have high-strain-rate-embrittlement effect (HSREE). This study tries to find weather the HSREE takes place in the high-strain rate deformation of a high ductile material pure iron DT8 to assess the possibility to cut the pure iron in its brittle state. Orthogonal high-speed cutting experiments were carried out with the highest cutting speed up to 9000 m/min. Chip formation by brittle fracture mechanism was captured when the cutting speed is higher than 8000 m/min. Brittle fracture characteristics, including transgranular and intergranular fracture morphologies in the chips at 8000 m/min show the pure iron becomes completely brittle at cutting speed of 8000 m/min. The result shows that it is possible to cut the high ductile material pure iron in its brittle state to avoid the problems incurred by its high ductility. [ABSTRACT FROM AUTHOR]