Computational study of Ti–6Al–4V flow behaviors during the twist extrusion process

Twist extrusion process which is based on the extrusion of a prism work piece through a die with a twist channel, is one of the severe plastic deformation (SPD) methods. In this investigation, the twist extrusion process under high pressure is simulated using the finite element method. The ABAQUS code is used for the FEM. The Johnson–Cook constitutive equation is used to describe the behavior of the Ti–6Al–4V alloy during the twist deformation. Since the deformations of Ti–6Al–4V alloy are performed at high temperature, therefore the effects of the temperature and strain rates under high pressure on the flow behavior are discussed. Furthermore, the magnitude of accumulative strain distributions which determines the sizes of final ultra fine grain (UFG) across the cross-section is presented. In this study, the modes of deformation during the twist extrusion process are also considered. It is found that both the pure shear and simple shear modes are present in the twist extrusion process across the sample. This procedure could be extended to other materials behavior, as well.