Multiscale Elastic Relaxation in Kinetic Monte Carlo via a Lanczos Technique: Nanostructure evolution

Keywords:
Lanczos, nanostructured material, Guinier-Preston zone

Abstract:
Elastic relaxation can make significant contributions to the morphological changes observed during micro/nanostructural evolution. A technologically important case is the formation of Guinier-Preston (GP) zones, the nanoscale copper platelet inclusions responsible for the hardening of aluminum in widespread use. These metastable particles are a few atoms thick, and up to 50 nm in diameter, length scales best suited for atomistic simulation such as a kinetic Monte Carlo approach; however, previously the cost of calculating the elastic relaxation ruled out simulations sufficiently long to observe the proposed vacancy-mediated diffusion process leading to the formation of the GP zones. The elastic energy of the entire system is a principal factor determining the formation of GP zones and their evolution during aging. Here we introduce a Lanczos method to calculate the elastic relaxation that is inherently multiscale in nature and speeds up the calculation of the relaxation sufficiently to allow observation of the Cu segregation process. We present the results of these stochastic simulations.

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Nanotech 2005 Conference Program Abstract