High-Pressure Double Torsion as a Severe Plastic Deformation Process: Experimental Procedure and Finite Element Modeling

Abstract

In the present study, a severe plastic deformation process of high-pressure torsion (HPT) has been modified. The new process is called high-pressure double torsion (HPDT) as both anvils of the conventional HPT process rotate in opposite directions. We manufactured sets of aluminum and pure copper samples using both the HPT process and the newly developed HPDT process to compare between microstructures and microhardness values. Our investigations showed that the copper samples processed by HPDT exhibited larger gradients in microstructure and higher values of hardness. Subsequently, we carried out a set of finite element simulations in ABAQUS/explicit to better understand the differences between the HPT process and the HPDT process. A comparison of the strain distributions of the HPT and HPDT samples revealed a decreasing trend in strain values as the radius increased at the middle surface of the samples. Analysis of the equivalent stress values revealed that stress values for the HPDT samples were higher than those of the HPT samples. Finally, the comparison of the max principal stress values indicated that in the HPDT sample, the extent of the compressive stresses was larger than those in the HPT sample.

Anisotropic modeling of structural components using embedded crystal plasticity constructive laws within finite elements

“…As shown, the copper plate exhibits very little plastic anisotropy due to almost random texture (Fig. 2), which is agreement with many other prior works [20,[71][72][73][74][75]. More importantly, the simple Voce law for the threshold stresses for the individual slip systems allows the VPSC model to adequately predict the constitutive response.…”

A study of microstructure-driven strain localizations in two-phase polycrystalline HCP/BCC composites using a multi-scale model

“…Manufacturing bulk MNCs usually involves employing a severe plastic deformation technique, such as equal channel angular extrusion, wire drawing and bundling, and accumulative roll bonding (ARB). These processes refine the initially coarse-structured metals to nano-structured metals without changing the original (bulk) dimensions of the sample (del Valle et al, 2005;Estrin and Vinogradov, 2013;Han et al, 1998;Jahedi et al, 2015a;Jahedi et al, 2015b;Jahedi et al, 2014;Komura et al, 1999;Manna et al, 2002;Saito et al, 1999;Valiev, 2004;Valiev and Langdon, 2006;Wu et al, 2001;Xue et al, 2007). The final sample forms include sheets, plates, rods, or wires.…”

Finite Element Modelling of High-Pressure Torsion: An Overview

“…FEM simulations were used to examine the influence of friction conditions on the material flow during HPT processing. 22,34,35,37,60,61) These simulations considered different friction models and coefficients for each region along the surface of the anvils. Figure 10 shows the distribution of equivalent strain in discs processed through 1/4 turn of quasiconstrained HPT using friction factors from 0 to 1.0 outside the depression area.…”