High thermomechanical loads in drilling of titanium alloys often cause significant alterations of the subsurface properties which are mostly connected to a degradation of the fatigue life of high dynamically loaded components. In the present study different drilling processes (conventional-, orbital- and vibration drilling), lubrication conditions (dry, MQL) and states of tool wear have been investigated regarding their influence on the subsurface properties of TiAl6V4. It was found that tensile residual stresses and increased hardness (result of severe plastic deformation) can be avoided if the process temperature and chip extraction are controlled.
Paulsen, T., Pecat, O., & Brinksmeier, E. (2016). Influence of Different Machining Conditions on the Subsurface Properties of Drilled TiAl6V4. In Procedia CIRP (Vol. 46, pp. 472–475). Elsevier B.V. https://doi.org/10.1016/j.procir.2016.04.047