Investigation of serrated chip morphology change regular in the burning of titanium alloys

Abstract

Titanium alloys are regarded as difficult-machining materials due to their high strength at elevated temperature, relatively low thermal conductivity, small elastic modulus, and high chemical reactivity. It is prone to produce cutting burn defect in end milling. In order to investigate the variation regular of serrated chip morphologies and the relationship between chip macro morphologies and tool flank wear in the burning of milling titanium alloys TC4, a series of cutting experiments were conducted in this study. The chip morphology and cutting vibration characteristic in different tool wear stages were examined using an optical microscope, SEM, and vibration test system. In addition, the variation characteristics of serrated chips in the burning of milling titanium alloy TC4 were analyzed. The results revealed that the occurrence of tool flank wear can make an influence on serrated chips morphologies and surface color in the cutting burning process. Besides, the chip segment degree, shear angle, and width of adiabatic shear band increased rapidly as the cutting burning occurring. The present research could be potentially used to evaluate tool wear and surface quality in the burning of end milling titanium alloy process.