Effect of α and β Phase Volume Fraction on Machining Characteristics of Titanium Alloy Ti6Al4V

Microstructure of titanium alloys has great influence on the manufacturing processes. In the current investigation the effect of change in volume fraction of alpha and transformed beta phase in the bimodal titanium alloy Ti6Al4V was discussed in relation with the mechanical and machining performance. The quenching process in STA (solution treatment and annealing) heat treatment was delayed by 30, 50 and 70 sec to get different microstructural morphology in each heat treated specimen. Face turning experiments with dry and high pressure coolant environment were performed on the solution treated samples. A detailed chip mechanism and microstructural analysis was performed to investigate the role of quench delay and subsequent change in phase volume fraction on thermal softening and frictional phenomenon in machining. The specimen treated with quench delay of 50 sec exhibited poor machinability because of thermal and frictional shock generated at the cutting zone.