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.

Wear and corrosion properties of AM70 magnesium alloy subjected to equal channel angular pressing (ECAP) were investigated using pin-on-disc dry sliding wear test and electrochemical impedance spectroscopy (EIS), respectively. Wear test was conducted with 30 and 40 N loads with sliding distance of 5000 m and at a constant speed of 3 m/s. Reduced coefficient of friction (COF) and wear mass loss of ECAP processed samples showed increased wear resistance. Worn surface analysis by scanning electron microscope (SEM) showed the presence of delamination, wear debris, and plowing. Energy dispersive X-ray spectrometer (EDS) revealed the occurrence of oxidation, and the wear mechanism was identified as abrasion and oxidation wear. EIS plots showed the improvement in corrosion resistance of ECAP processed magnesium alloy compared to initial condition due to grain refinement and homogeneous distribution of secondary particles.

Deformation mechanics in equal channel angular pressing (ECAP) was studied in situ using digital image correlation (DIC) and infra-red (IR) thermography. In a prototypical experiment in an optical and IR transparent die, the deformation of commercially pure lead (Pb) is observed using high-speed optical and IR cameras. From the resulting time-sequence images of metal-flow in the deformation zone, DIC is used to characterize the zone of severe plastic deformation (SPD) as a function of the scale of deformation (sample dimensions), deformation speed, and die geometry. The temperature rise in the deformation zone was characterized using IR thermography and the results were compared against theoretical estimates. These observations provide direct insights into the mechanics of SPD in ECAP, which can offer strategies for microstructure control, process optimization, and miniaturization of ECAP.

Equal channel angular pressing is both a novel and an industrialized process among severeplastic deformation methods to fabricate ultra-fine-grained metals and alloys.Verification of a three-dimensional finite element model which compares various strengthcoefficients and strain-hardening exponents (virtual materials) defined for the plasticdeformation behavior of materials was performed with experimental tests. The virtualprocess numerically analyzed the effects of the strain behavior and pressing force. Theresults show that strength coefficient enhancement leads to decreased effective strainvalue, heterogeneous strain distribution and higher pressing force, and an increment inthe strain-hardening exponent results in lower pressing force. However, this parameterdoes not have an obvious effect on the effective strain magnitude and strain dispersaluniformity. Furthermore, the highest imposed effective strain, the best straindistribution homogeneity and the lowest required punch load were achieved for the deformedmaterial with the lowest strength coefficient and highest strain-hardening exponent.

The effectiveness of different routes of equal channel angular pressing (A, Bc, and C) is studied for commercially pure copper. The stored energy and the activation energy of recrystallization for the deformed samples were quantified using differential scanning calorimetry and X-ray diffraction line profile analysis. Results of the study revealed that the dislocation density and the stored energy are higher in the case of route Bc deformed sample. The activation energy for recrystallization is lower for route Bc.