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Deformation Mechanisms of Nanocrystalline Hexagonal Close-Packed Metals

Published online by Cambridge University Press:  01 February 2011

Guangping Zheng*
Affiliation:
gpzheng@hku.hk, University of Hong Kong, Department of Mechanical Engineering, Pokfulam Road, Hong Kong, N/A, 10000, China, People's Republic of
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Abstract

Using molecular dynamics simulation of nanocrystalline (nc) samples with grain size of 10 nm, a reverse martensitic transformation from hexagonal close-packed (hcp) to face-centered cubic (fcc) structure is observed in nc-cobalt and nc-zirconium undergoing plastic deformation. In nc-cobalt hcp-to-fcc transformation is prevalent and deformation twinning is rarely observed. The transformation mechanism involves the motion of Shockley partial dislocation 1/3<1100> in every other (0001)hcp /(111)fcc plane. In nc-zirconium the hcp-to-fcc transformation competes with the deformation twinning. From the simulation results, it is suggested that the interaction among partials should be considered to understand the deformation mechanisms of hcp nc metals.

Type
Research Article
Copyright
Copyright © Materials Research Society 2006

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