Effects of different tool microstructures on the precision turning of titanium alloy TC21

Titanium alloys are widely used in the aviation field due to the excellent properties, such as high specific-strength and high-temperature resistance. But the poor machinability of titanium alloys has brought the great difficulty to its machining process. In the cutting process of titanium alloys, tool wear is very serious, and the machining quality is difficult to be guaranteed. As a new type titanium alloy, TC21 alloy has the higher strength and its machinability is less than other titanium alloys. Aiming at the cutting defects in the cutting process of TC21 alloy, three different microstructures, including parallel, perpendicular and wavy grooves, are presented and cut on the rake surface of tools by the laser texturing method. A series of precision turning process of TC21 alloy are implemented on the precision machine using the inserts with different microstructures. The effects of the different microstructures on the chip morphology, turning force, surface morphology, and surface roughness are investigated deeply. The results demonstrates that the tool microstructures have very important role on the turning process of titanium alloys and the wavy microstructure has the best effect in improving the machinability of titanium alloy TC21.