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

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.