Numerical Simulation of Surface Modification in Dry and Cryogenic Machining of AA7075 Alloy

Functional performance of a machined product is strongly influenced by its surface characteristics that are frequently modified from the process. These changes must be taken into account when modeling the machining process.This work presents the modeling of grain size and hardness changes induced during turning of AA 7075-T651 alloy using the Finite Element (FE) method. The implemented user subroutine is able to describe the microstructural changes and the dynamic recrystallization in order to correctly simulate the formation of new grains and their influence on the material flow stress. The model is experimentally calibrated and validated to predict the evolution of the surface conditions (grain size, hardness, etc.) when varying the cutting speeds and tool nose radii. All simulations were performed for dry and cryogenic cutting conditions using uncoated carbide tools.