Cutting zone area and chip morphology in high-speed cutting of titanium alloy Ti-6Al-4V

The titanium alloy Ti-6Al-4V has superior properties but poor machinability, yet is widely used in aerospace and biomedical industries. Chip formation and cutting zone area are important factors that have received limited attention. Thus, we propose a high-speed orthogonal cutting model for serrated chip formation. The high speed orthogonal cutting of Ti-6Al-4V was studied with a cutting speed of 10-160 m/min and a feed of 0.07-0.11 mm/r. Using theoretical models and experimental results, parameters such as chip shape, serration level, slip angle, and shear slip distance were investigated. Cutting zone boundaries (tool-chip contact length, length of shear plane, and critical slip plane) and cutting zone area were obtained. The results showed that discontinuous, long-curling, and continuous chips were formed at low, medium, and high speeds, respectively. Serration level, shear slip distance, and slip angle rose with increasing cutting speed. The length of shear plane, tool-chip contact, and critical slip plane varied subtly with increased cutting speed, and rose noticeably with increased feed. Cutting zone area grew weakly with increased cutting speed, levelling off at high cutting speed; however, it rose noticeably with increased feed. This study furthers our understanding of the shear slip phenomenon and the mechanism of serrated chip formation.