Stress and strain distribution in twist extrusion of AA6063 aluminum alloy

Twist extrusion is one of the common methods in the area of severe plastic deformation. By passing the sample through a twist channel grain refinement will occur. In this article, the twist extrusion process is modeled by ABAQUS finite element software. Three different approaches are used for prediction of strain field distribution for higher passes of TE. The FE results are compared with the experimental results of twist extruded AA6063 aluminum alloy specimens. A sensitivity analysis has been implemented to choose the proper element size and friction coefficient during simulation. The microstructures of TE samples have been observed by SEM microscopy and analyzed by Pixcaviator software. Comparing the results of the microstructure study and FE shows that importing the material properties and deformation field from the previous pass to the current pass is the best way to simulate a multi-pass twist extrusion process. The plastic strain distributions show that the effective plastic strain is higher at the corner of the samples than at the center of it. The FE results show that the maximum Von-Mises stress increases at the corner elements by increasing the extrusion passes from 42 MPa at pass #1 to 110 MPa at pass #7. Most of this increase occurs in the first three passes.