Visco-plastic self-consistent modeling of crystallographic texture evolution related to slip systems activated during machining Ti-6AL-4V

Abstract

Exploring the interconnection between texture variation and the activations of slip systems is vital for the texture generation and controlling during machining of Ti-6AL-4V. The evolution of crystallographic texture and the activations of different slip systems during machining of Ti-6AL-4V were studied combined with the orientation imaging microscopy (OIM) and visco-plastic self-consistent (VPSC) framework. A VPSC model considering the activations of five slip families as well as twinning of hexagonal close packed (HCP) Ti structure and coupled with a finite element cutting simulation model were used to simulate the texture variations during machining of Ti-6AL-4V. Crystallographic texture evolutions of Ti-6AL-4V in chips and machined surface were examined using OIM. Two initial textures of Ti-6AL-4V yielded the same end texture, a strong C fiber texture. Lastly, Voce hardening parameters were modified to control the activations of slip modes as well as twinning and calibrate the VPSC simulation results of texture and mechanical property. It is found that the combination of prismatic <a>, basal <a>, pyramidal <a> and 2-nd order pyramidal <c+a> slip systems induce the generation of C shear texture in machining of Ti-6AL-4V. The activation of 2-nd order <c+a> slip system makes large contribution to the formation of C shear texture irrespective of the initial textures and machining parameters. The result demonstrates that activations of slip systems and their relative activities depend on the shear deformation in machining of Ti-6AL-4V. This finding is important to control the texture variation in the deformation of Ti-6AL-4V.