Cyclic plasticity phenomena as predicted by polycrystal plasticity

The elasto-viscoplastic Taylor-Lin model of polycrystal plasticity is emplo yed to simulate the cyclic behavior of polycrystalline metals. Uniaxial ten sion-compression as well as biaxial cyclic deformations are examined by imp osing the strain amplitude. Microscopic hardening law is used to account fo r the self and latent hardening of the slip systems. It is shown that the p olycrystal plasticity model is able to reproduce all basic phenomena observ ed in cyclic loading experiments. These are: Bauschinger effect, single sli p at low plastic strain amplitudes, cyclic hardening and softening, indepen dence of the stress amplitude from the average strain, the hysteresis memor y, and finally the out-of-phase hardening in biaxial fatigue. Important cha nges in the average activity of slip systems were observed in the simulatio ns which are consequences of the elasticity and hardening of the material a nd can be related to the appearance of the PSBs. (C) 2000 Elsevier Science Ltd. All rights reserved.