Finite element analysis of material deformation behaviour during DRECE: the sheet metal SPD process

The material deformation behaviour during the innovative SPD process called DRECE (Dual Rolls Equal Channel Extrusion) has been analysed by FEM simulations. In the process, a workpiece in the form of a strip is subjected to plastic deformation by passing through the angular channel; however, the workpiece dimensions remain the same after a pass is finished. Performing consecutive passes allow for increasing the effective strain in the material to a required level. In the conducted simulations two various channel angles (108 degrees and 113 degrees) have been taken into consideration, as well as two processing routes, A and C (without and with turning the strip upside-down between consecutive passes, respectively). The analysis of simulation results has revealed that significant strain and stress inhomogeneities across the strip thickness are generated in a single DRECE pass. The die design (the inner and outer corner radius) and friction conditions affect the material flow, reducing significantly the shear strain in the near-surface regions of the strip. The strain inhomogeneity can be effectively reduced by choosing the processing route C. The strain distributions and the corresponding tensile test results have confirmed that the smaller channel die angle allows to generate larger strain and higher strength of the strip but also reduces its ductility more than the die setup with the larger channel die angle.

Automated summary

The material deformation behavior during the DRECE process has been analyzed using FEM simulations. The simulations considered two different channel angles and two processing routes. The results showed significant strain and stress inhomogeneities across the strip thickness, which can be mitigated by choosing a specific processing route. The smaller channel die angle generates larger strain and higher strength of the strip, but reduces its ductility.