Constitutive model incorporating the strain-rate and state of stress effects for machining simulation of titanium alloy Ti6Al4V

Ti6Al4V titanium alloy is widely used in aero-engines due to its superior performance. However, as a difficult-to-cut alloy, it induces short cutting tool life and poor surface integrity. To improve these process outcomes, numerical simulations are of importance. The predictive ability of such simulation depends on the accuracy of the constitutive model which describes the work material behavior under loading conditions specific to metal cutting. Therefore, the focus of this paper is the formulation of a constitutive model to be used in the orthogonal cutting simulation of Ti6Al4V. The distinguished feature of this model is its simplicity, accounting for the strain-rate and state of stress effects in the work material deformation and fracture. The model coefficients were identified using mechanical tests and numerical simulations with specially-designed test specimens to cover a wide range of strain-rates and state of stress. Orthogonal cutting simulations were performed and the obtained results were compared with those measured.