Influence of the initial yield strain magnitude on the materials flow in equal-channel angular extrusion process

The influence of initial yield strain, material nonlinearity characteristics (perfectly plastic, strain hardening and strain softening) and die geometry on the deformation behaviour of a sample in an equal-channel angular extrusion process was simulated by the finite element method. The results indicate that plastic strain heterogeneity and sample bending increase with initial yield strain magnitude while the maximum processing load is reduced. In order to validate the numerical results, experiments were conducted on representative polymers.