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Metastable beta titanium alloys combine excellent mechanical properties with low density, and are therefore very attractive in many mechanically demanding applications. The high strength and hardness, however, cause several challenges in the machining of these materials, and the machining costs of titanium components can be significant compared to the overall costs of the component. The cutting conditions can be optimized using finite element simulations, leading to reduced machining costs and improved machining quality. However, the simulations of the rather complex machining processes need reliable material models. The models can only be generated when the mechanical behavior of the material is well understood. In this work, the mechanical response of Ti-15-3-3-3 alloy has been characterized in a wide range of strain rates and temperatures. The Johnson-Cook material model was fit to the measurement data, and the model was used to simulate orthogonal cutting of the material. The simulation results were further compared to cutting experiments at high cutting speeds. The current model is able to simulate the serrated chip formation frequently observed in machining of titanium alloys at high cutting speeds. Also, the simulated cutting forces match well with the experimentally obtained forces. However, the model needs to be further developed to match also the fine details of the chip, such as the chip curl and thickness of the individual serrations. |
