Degree Name

Doctor of Philosophy


School of Mechanical, Materials and Mechatronic Engineering


Severe plastic deformation (SPD) has been the subject of intensive investigations in recent years because of the unique physical and mechanical properties of ultrafine grained (UFG) materials fabricated by this technique. Equal channel angular pressing (ECAP) is the most frequently used SPD technique due to its efficiency in grain refinement. The deformation mechanism during the ECAP process is very complicated and it has always been assumed to be a simple shear along the intersecting plane of two ECAP channels in most published literatures. A number of experiments and numerical simulations have revealed that the simple shear based theory could not accurately predict the microstructure development, plastic strain (or strain rate) distributions and texture evolutions. Even though many studies have contributed to understanding of the deformation mechanism of the ECAP process, some research areas have still not been fully explored, such as texture modelling. Up to now, few texture simulations in the literatures have been carried out based on the real full-scale ECAP process and most of them were conducted using the simple shear theory. Therefore, a systematic study on modeling of texture evolution of the real ECAP process and investigation of the effects of the ECAP parameters on texture evolution are essential.

In the present study, a crystal plasticity finite element method (CPFEM) model has been developed to offer a systematic understanding of the deformation behavior and texture evolutions of single crystals, bicrystals and a polycrystal during the full scale ECAP processes. The developed CPFEM model has been validated by comparing the simulation results with the experimental observations.