Laser-assisted milling of Ti-6Al-4V with the consideration of surface integrity

Abstract

Titanium alloys are well known for their excellent strength-to-weight ratio and corrosion resistance and is highly sought after in the aerospace industry. This study focused on experimental evaluation of laser-assisted milling (LAML) of a Ti-6AL-4V (Ti-64) workpiece which uses localized preheating of the workpiece by a laser and characterizes the improvements to the machinability of these metals. The benefits of LAML are quantified for laser parameters which are shown to maintain final surface integrity of the heat-treatable workpiece after the machining process. Laser parameters are determined based on temperature prediction modeling. Laser preheating is shown to reduce cutting force during the machining process. Machinability improvement is characterized through inspection of flank wear on the cutting tool using LAML and traditional machining methods and comparing total tool life. Systematic characterization of samples is performed using hardness measurements, scanning electron microscopy (SEM), and X-ray diffraction (XRD) to ensure that material properties remained unaltered as a result of laser preheating. An economic analysis is performed for LAML to characterize the improvement obtained despite the additional costs associated with the laser equipment.