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Size-dependent plastic deformation characteristics in He-irradiated nanostructured Cu/Mo multilayers: Competition between dislocation-boundary and dislocation-bubble interactions.
- Source :
-
Materials Science & Engineering: A . Sep2016, Vol. 673, p530-540. 11p. - Publication Year :
- 2016
-
Abstract
- Nanoindentation methodology was used to investigate the plastic deformation characteristics, including the hardness ( H ), strain rate sensitivity (SRS, m ) and activation volume ( V * ), of Cu/Mo nanostructured metallic multilayers (NMMs) with equal layer thickness ( h ) spanning from 10 to 200 nm before and after He-implantation at room temperature. Compared with the as-deposited Cu/Mo NMMs, the irradiated Cu/Mo samples exhibited the enhanced hardness particularly at great h , which is caused by the bubble-hardening effect. Unlike the as-deposited Cu/Mo NMMs displayed a monotonic increase in SRS (or a monotonic decrease in activation volume) with reducing h , the irradiated Cu/Mo samples manifested an unexpected non-monotonic variation in SRS as well as in activation volume. It was clearly unveiled that the SRS of irradiated Cu/Mo firstly decreased with reducing h down to a critical size of ~50 nm and subsequently increased with further reducing h , leaving a minimum value at the critical h . These phenomena are rationalized by considering a competition between dislocation-boundary and dislocation-bubble interactions. A thermally activated model based on the depinning process of bowed-out partial dislocations was employed to quantitatively account for the size-dependent SRS of Cu/Mo NMMs before and after irradiation. Our findings not only provide fundamental understanding of the effects of radiation-induced defects on plastic characteristics of NMMs, but also offer guidance for their microstructure sensitive design for performance optimization at extremes. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09215093
- Volume :
- 673
- Database :
- Academic Search Index
- Journal :
- Materials Science & Engineering: A
- Publication Type :
- Academic Journal
- Accession number :
- 117496171
- Full Text :
- https://doi.org/10.1016/j.msea.2016.06.071