Improvement of Ti–6Al–4V surface integrity through the use of high-speed ultrasonic vibration cutting

High-speed ultrasonic vibration cutting (HUVC) has been demonstrated to be a good machining technique for titanium alloys. However, although surface integrity is known to strongly impact the service performance of components (e.g., wear resistance and fatigue performance), the surface integrity of titanium alloys machined via HUVC has not been investigated. In this study, the effects of HUVC on various aspects of the surface integrity of Ti–6Al–4V were investigated. First, the ironing effect of HUVC was analyzed. Then, an experiment for comparing the HUVC technique to a conventional cutting (CC) technique was carried out under the conditions of a cutting speed range of 100–400 m/min. The specimens subjected to HUVC were found to have lower surface roughness, a more uniform surface texture, a thicker subsurface deformation layer (27–82 µm), and higher surface micro-hardness (413–472 HV_0.2) and compressive residual stress (−574 to −925 MPa in the feed direction) than those subjected to CC.