1. High-speed creep process mediated by rapid dislocation absorption in nanocrystalline Cu.
- Author
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Mu, Junwei, Jiang, Zhonghao, Zheng, Weitao, Tian, Hongwei, Lian, Jianshe, and Jiang, Qing
- Subjects
NANOCRYSTALS ,NUCLEATION ,CREEP of copper ,MATERIAL plasticity ,PHYSICS - Abstract
A high-speed creep process mediated by rapid dislocation absorption was found in the nanoindentation creep test on nanocrystalline Cu. The creep strain and creep strain rate depend strongly on the loading strain rate and are far higher than those predicted by the models of Coble creep and thermally activated grain boundary sliding. Our analysis revealed that grain boundary dislocation sources can be activated and emitted dislocations from grain boundaries can be stored effectively at a high loading strain rate, but cannot at a low loading strain rate. The observed high-speed creep process is mediated mainly by the rapid absorptions of the stored dislocations and the dislocations newly nucleated during the holding period. An implication of our experimental finding is that dislocation structure in nanocrystalline metals is highly unstable and dislocation activity can proceed after loading and lead to a significant post-loading plasticity. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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