Advanced finite element model for predicting surface integrity in high-speed turning of AA7075-T6 under dry and cryogenic conditions

Abstract

The overall quality of a component and its mechanical performance and reliability during all its life cycle depend on several characteristics. The choice of the material plays an important role in satisfying the requirements and usually it makes the difference between failed and not failed products; however, another significant impact in the material performances is characterised by the manufacturing process. Nowadays, the numerical simulation represents an important tool to quickly predict several scenarios depending on process parameters’ changes, leading to a more flexible manufacturing process and time–cost saving due to the reduced experimental tests. This work presents an innovative finite element model (FEM) of high-speed turning of one of the most used aluminium alloys in aerospace field, namely the AA7075-T6. The developed simulation tool allowed to better investigate the metallurgical phenomena triggered by the varying process parameters tested and the cooling conditions used during the machining tests. A physics-based model to simulate the material behaviour has been developed and implemented via subroutine within the FEM software. The predictive capability of the model has been validated through experimental and numerical comparison of cutting forces, maximum temperature and grain size changes. The developed 3D FE model is capable of including the effects of different cooling conditions during machining of the aluminium alloy AA7075-T6 on the surface integrity (e.g. the microstructure and the dislocation density variation), whilst evaluating further important manufacturing process variables as cutting forces and maximum temperature.