Material model assessment in Ti6Al4V machining simulations with FEM

Abstract

Ti6Al4V alloy is a well-known difficult-to-cut material used in different industrial applications, to achieve the expected component quality, proper definition and control of the machining process parameters must be accomplished. To address this problem, simulations with finite element method (FEM) seem to be an interesting engineering tool to model and optimize machining processes. Nevertheless, the model capability in capturing the behaviour observed in real machining processes is associated with the definition of the model and parameters that describe the workpiece flow stress. This contribution aimed to study the performance of built-in AdvantEdge-2DTMmaterial laws applied in Ti6Al4V orthogonal cutting simulations under dry conditions. The numerical models were created under three levels of cutting speed, a constant feed rate and depth-of-cut, a variable tool rake angle (of 20° and -6°/0 °), but also using four Ti6Al4V constitutive laws, namely, one suggested in AdvantEdgeTM library, a Johnson- Cook (JC) model, a Power law (PL) and a PL coupled with ductile damage model. Experimental results were used to assess the numerical models’ accuracy in predicting the machining forces and metal chips. Satisfactory results regarding the machining forces prediction were achieved with all material laws, yet when the damage criterion was coupled with the constitutive laws (PLD and AE standard material law), the simulations were also were able to achieve the expected chip morphology (serrated metal chips). Keywords: Ti6Al4V, AdvantEdge, orthogonal cutting, power law, Johnson-Cook material model, machining forces, saw-tooth chips.