| Budget Amount *help |
¥5,600,000 (Direct Cost: ¥5,600,000)
Fiscal Year 1996: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1995: ¥4,000,000 (Direct Cost: ¥4,000,000)
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| Research Abstract |
First, we simulate Frenkel-Kontorova model with the use of molecular dynamics method, and obtain velocity for kink propagation, nucleation rate for a kink-pair and velocity for a dislocation. In order to simulate the system at a constant temperature, we treat the equation of motion under the influence of random force (thermal noise) and friction force. The simulation results are in good agreement with theoretical results which are calculated from our constraint method and the transition state theory.
Secondly, we modify the constraint method to apply it to a 2-dimensional lattice model for screw dislocations in b.c.c.crystals and obtain Peierls stress and core structure of a dislocation. We obtain two kinds of core structure, isotropic and polarized configurations, which are observed by Takeuchi et.al. The results for Peierls stress are twice as many as simulation results of Takeuchi et.al.in their computer simulation. We consider that the difference between our and the simulation results for Peierls stress is attributed to the different condition between our and their studies. That is, they apply an external stress to obtain Peierls stress. On the other hand, we do not apply any external stress, but use constraint conditions to stop the dislocation at any places.
To obtain the above results, we use the work-station, two X-terminals, CD-ROM drive and lap-top personal computer which we get by this GRANT-IN-AID FOR SCIENTIFIC RESEARCH.We present our research in the International Conference on Computer Simulation in Materials Science in Ile de'Orelon, France, 1995, the 6th Forum for Lattice Defects "Dislocations-Present and Future Perspectives-" in Yamaguchi, 1996 and so on.
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