Comparative investigation of surface integrity in laser assisted and conventional machining of Ti-6Al-4 V alloy

Abstract

Titanium alloys have numerous applications in the aerospace and medical industry due to their high strength and low weight. In the manufacturing of aerospace parts, surface integrity plays a key role due to its strong relationship with fatigue life and performance of the components. Since titanium alloys are difficult-to-machine, their Conventional Machining (CM) provides some technical limitations. As an alternative method, Laser-Assisted Machining (LAM) can be employed for this purpose and it is recommended for machining of hard materials. Laser Machining is the hybrid machining technique in which laser radiation is localized in front of cutting zone. However, surface integrity of the machined part should be controlled in LAM process due to the thermal effects of laser beam in to the workpiece material. Therefore, at the present study, experimental investigations were performed for both conventional and laser-assisted machining of Ti-6Al-4 V alloy and their results on surface integrity were compared and discussed together. In this regard, important indications of surface integrity including microhardness, grain size, surface roughness as well as thermal loads generated during the removal process were evaluated at different machining parameters. The results demonstrated that the use of laser-assisted machining under controlled process conditions can be significantly useful for improvement of surface integrity indications in machining of Ti-6Al-4 V superalloy.