Optimized tool design for expansion equal channel angular extrusion (Exp-ECAE) process using FE-based neural network and genetic algorithm

Applying hybrid equal channel angular pressing (HECAP) to pure copper using optimized Exp.-ECAP die

“…The biggest reason for this is that the increasing extrusion rate is not reflected in the strain value as it should be in the theoretical equation which is shown in Eqn (5). This has been explained in detail by Fereshteh-Saniee et al [22]. After a certain extrusion ratio, some part of the specimen remains constant in the spherical cavity and the extrusion rate takes a smaller value than it is.…”

“…Optimization of an Exp.-ECAP die was previously done by Fereshteh-Saniee et al [22]. However, in the mentioned study, optimization was done separately for two different objective functions.…”

“…These geometric parameters are the channel diameter (D 0 ), the diameter of the spherical cavity (D 1 ), the fillet radius (r), and eccentricity of the cavity center with respect to the intersect of the centerlines of the channels (e). These parameters were nondimensionalized as in the reference study as follow [22]:…”

“…After that, the design of the experiment was carried out by adhering to the limit values obtained for dimensionless parameters in the reference study [22]. A total of 30 experiments were determined to be simulated using the finite element method and were shown in Table 1.…”

“…For this reason, it is a preferred metal in many SPD works [14][15][16][17][18][19][20]. Although the Exp.-ECAP process has been applied for some aluminum and magnesium alloys [13,21,22], it has not been applied before for pure copper.…”