Surface Integrity study in cryogenic milling of Ti-6Al-4V titanium alloy

Titanium alloys, such as Ti-6Al-4V, are widely used in aerospace and biomedical fields due to their superior properties, but machining these materials remains a significant challenge. This study investigates the effects of cryogenic machining on the surface integrity of Ti-6Al-4V. Experimental milling tests were conducted under varying cutting conditions of feed and cutting velocities, focusing mainly on residual stresses. It was found that residual stresses are affected mostly by the feed per tooth. A preliminary Finite Element Model was developed and validated, across different cutting conditions, to predict residual stresses in cryogenic machining, incorporating both mechanical and thermal aspects. Maximum error of 9% was observed on the residual stress estimation, both considering the residual stresses on the surface and the maximum compressive values. Higher errors were found regarding the estimation of the depth of the maximum compressive stresses.