Equal channel angular pressing with rotating shear plane to produce hybrid materials with helical architecture of constituents

A modification of the metal processing technique known as equal channel angular pressing (ECAP) to incorporate shear plane rotation, called ECAP-R, is presented. The new process was developed to produce hybrid materials with helical architecture of their constituents, which holds promise to enable enhanced mechanical properties. The process was trialled experimentally using a specially designed laboratory-scale rig. It was shown that a positive mean stress (negative hydrostatic pressure) in a part of the multipiece billet leads to separation of the constituents within that region. A way to improving the process design was suggested based on finite element simulations. It was demonstrated that the proposed processing results in excellent bonding between the helical parts of the hybrid in the regions of positive hydrostatic pressure. Subsequent annealing gave rise to further improvement of the quality of bonding. Processing by ECAP-R at elevated temperatures was suggested as a viable method of producing hybrid materials with helical architecture.