A planar twist channel angular extrusion (PTCAE) as a novel severe plastic deformation method based on equal channel angular extrusion (ECAE) method

Planar twist channel angular extrusion (PTCAE) is a new severe plastic deformation method to produce bulk ultra-fine-grained materials which is based on conventional equal channel angular extrusion by applying additional planar twist strain in deformation zone of ECAP process and simultaneously imposing larger strain and increasing severe plastic deformation methods efficiency. Plastic deformation characteristics of PTCAE method were analyzed through finite element analysis using Deform 3D V.5 software, processing loads and values of effective strain in different directions of sample were studied for different planar twist angles (α) in comparison with the results of conventional ECAP with the same channel dimension and arc of curvature angles. Die and punch were assumed as rigid bodies, whereas the billet, with dimensions of 10 mm × 10 mm × 70 mm was considered to be deformable pure aluminum. The processing conditions such as friction coefficient, ram speed, mesh size and other factors were held constant to make comparison between the different processing conditions possible. The results indicated that more strain values with more uniform distribution may be achieved after PTCAE method in comparison with the conventional ECAP method. Also, it is observed that in α = 20, the equivalent strain distribution is homogenous approximately in both of vertical and horizontal directions of the cross-section of the sample. Therefore, PTCAE can be considered as a promising severe plastic deformation technique for future industrial applications which can be installed on any standard extrusion equipment without any additional required facilities that are essential in other new severe plastic deformation methods and can be used instead of ECAP process significantly and beneficially.