Conclusions :

  • The first dissipation regime, which occurs at low concentrations and low couplings, may be called as the dislocation induced Cottrell relaxation DICR (or dislocation enhanced Snoek relaxation, DESE) for spherical point defects. This relaxation is related to the energy dissipation of isotropic point defects during their irreversible hopping motions (short range drift-diffusion) in the temporal and spatially fluctuating stress field of oscillating kinked-dislocations in bcc metals, when one has very loose coupling between the assemble of mutually interacting kinks and the point defects sub-system.
  • At high coupling constant and core concentrations products , completely different type of damping peak behavior is observed where peak high (relaxation strength) stays constants but the peak position shows steady shift towards the higher temperatures upon any increase in the mean dislocation core concentration and/or coupling ratio. This strange collective and correlated behavior of point defects in the formation of SKR is discovered by Ngai and Magalas by carefully examine the relaxation peak shape in terms of asymmetry and the analogous behavior of dielectric relaxation, which shows some universality.
  • Our experience with this model gave the result that, in the aging event, which causes the disappearance (or reduction of strength in a very high amount) of dislocation enhanced Snoek peak and appearance of Snoek-Koster peak, the controlling mechanism is the long range diffusion of interstitials from bulk to dislocation core. But the stabilization of Snoek-Koster peak can happen by the segregation of interstitials on dislocation kinks by the short-range diffusion along the dislocation and /or long-range diffusion controlled bulk segregation. Both events are successfully simulated in this study.
  • Two types of anomalous amplitude dependence and tearing of Cottrell atmosphere have been observed in our computer simulation experiments. Namely, in the transition regime and in the SKR regime, where one detects completely different shapes of stationary point defect cloud formations. In the first case, one observes dumbbell formation and in the second case singled formation having an irreversible shift towards one of those two extreme kink positions, where the kink has maximum lifetime.
  • The limiting strain amplitude for anomalous amplitude dependence of cold-work peak is a function of average concentration of interstitials on dislocation, which was predicted by Ogurtani [12].