Finite element investigation of equal channel angular extrusion with back pressure

The back pressure in equal channel angular extrusion (ECAE) can produce more uniform and increased strain level into the workpiece, consequently obtaining the improved material property of the workpiece. It also has advantages in fabricating the materials without forming defects by giving the compressive pressure to the material surfaces. This study numerically investigates the effect of back pressure on material behavior and strain distribution of the commercially available pure titanium (CP-Ti) specimen. The back pressure effect in multi-pass ECAE process was also examined. Three types of the die tooling termed as Type-I, Type-II and Type-III to apply back pressure were examined under the plane-strain and non-isothermal conditions. From the simulation results, it was found out that the back pressure applied to the ECAE greatly increased the strain level accumulated without reducing the uniformity of the strain distribution.