Investigation of Ti-6Al-4V surface integrity from milling process

Abstract

The applications of titanium alloys vary from aerospace industry, medical device and military, however having many challenges in the machining process due to difficult-to-machine characteristic of the material. This study focused on surface integrity of titanium alloy grade Ti-6Al-4V after milling process with different set of parameters. This research investigates the effect of surface integrity of titanium alloys (Ti-6Al-4V) after milling operation with difference cutting parameters such as feed rate, depth of cut and cutting speed. Characterization and measurements were taken on the surface morphology, residual stress, surface roughness and surface hardness. It was found out that from the experiment, the highest cutting speed at 8000 rpm produced lowest surface roughness value of 2.066 μm, while lowest cutting speed at 4500 rpm produced highest surface roughness of 2.55μm. The residual stress analysis shown that all the surfaces produced compressive stresses of more than 500 MPa. It is also found out no evidence of transformation at the morphology of the machined surface. Microhardness measurement at the depth 10 μm to 500 μm from the machined surface only shows slight increase of hardness, however, at the range from machined surface to 10 μm indicates low hardness due to softening effect from the machining process. This demonstrated that surface integrity of titanium alloys does effect by the machining parameters.