Numerical and Experimental Comparison of ECAP and DECLE Processes during High-Temperature Deformation of AA۷۰۷۵

Plastic strain distribution at high temperatures plays a crucial role in mechanical properties of deformed material during severe plastic deformation (SPD). In present study, plastic strain distribution at ۴۰۰°C was investigated for aluminum ۷۰۷۵ alloy by comparing two different SPD techniques known as dual equal channel lateral extrusion (DECLE) and equal channel angular pressing (ECAP). The comparative study was made by applying simulated and experimental methods. Performing numerical simulation by Arrhenius-type constitutive equation is preferred to Johnson-Cook model as it considers the coupled effect of strain rate and temperature. This results more prediction accuracy of flow stress at high temperatures. Results of simulation show that the amount of average plastic strain obtained in each pass of DECLE process is larger than that obtained in ECAP process. Similarly, more homogeneous plastic strain is achieved within DECLE-processed material in each pass. In addition, the macro-crack nucleation in DECLE-processed sample is more possible. Results of tensile tests demonstrate larger yield and ultimate tensile strength by DECLE process in comparison with ECAP process.