Overview Simulations: Selective Kink Decoration Model Modeling Results Conclusion Interactive Geometric Kink Model Modeling Results Conclusion

© 2005 CSL

Figure 1. Effect of average concentration of interstitials along the dislocation line on the mechanical spectrum. Stable peaks are obtained by keeping average concentration constant and utilizing extremely low cooling rate. DICE (Dislocation Induced Cottrell Effect) type of peaks at low concentrations and C-K (Cottrell-Koster) type of peaks at high concentrations are observed.

Figure 2. The amplitude dependence of mechanical spectrum.

A. Amplitude independent regime. (F < 1)
B. Anomalous amplitude dependence regime (as observed by Prof. Ke in Al-Mg alloys). (F >2) Sudden decrease of peak height after the force amplitude 2 because of the tearing of Cottrell atmosphere and formation of quasi-static Boltzman dumbbell shape clouds formation.

Figure 3. The concentration profiles of point defects in the vicinity of a kink for different force amplitedes in the DICE regime. The dumbbell shape quasi-static Boltzman atmosphere frmation can be seen after the Cottrell atmosphere is torn off.

Figure 4. The aging behavior of dislocation induced Cottrell peak during the heating and cooling cycle where no bulk segregation takes place.

Figure 5. The concentration profiles around the moving kink during the heating and cooling cycle where dislocation damping in the DICE relaxation regime.

Figure 6. The mechanical spectrum obtained by the simultaneous bulk segregation of interstitials in the dislocation core region during the continuous heating and cooling cycle.

On heating, DICE and C-K peaks are appearing on the right and left sides of the damping coefficient versus inverse temperature plot, respectively.

On cooling, C-K peak completely stabilized showing increase in strength and shift in the position, while DICE peak disappears from the spectrum.

Figure 7. The Peaking Effect associated with a DICE peak during the aging at the low temperature shoulder of the stabilized peak.