Access count of this item: 349
|Title:||Specimen- and grain-size dependence of compression deformation behavior in nanocrystalline copper|
|Authors:||Okamoto, Norihiko L. |
Hirato, Tetsuji https://orcid.org/0000-0003-3030-1632 (unconfirmed)
|Author's alias:||岡本, 範彦|
Crystal plasticity (B)
Polycrystalline material (B)
Mechanical testing (C)
Focused ion beam (FIB) method
|Journal title:||International Journal of Plasticity|
|Abstract:||The compression deformation behavior of electrodeposited nanocrystalline copper pillars with average grain sizes (d) of 360, 100, and 34 nm has been investigated as a function of specimen size (D). The yield stress for nanocrystalline pillars with d = 360 and 100 nm does not depend on specimen size, exhibiting essentially the bulk yield stress until the specimen size is reduced down to the critical values ((D/d)∗ = 35 and 85), below which the yield stress decreases with the decrease in specimen size. In contrast, the yield stress for nanocrystalline pillars with d = 34 nm does not depend much on specimen size, exhibiting the bulk yield stress value for all specimen sizes investigated. The dominant deformation mechanism changes from dislocation glide for pillars with d = 360 and 100 nm to grain boundary diffusional creep for pillars with d = 34 nm. Grain-size induced softening occurs for pillars with d = 34 nm being consistent with the occurrence of change in deformation mechanisms, whereas the bulk yield stress for pillars with d = 360 and 100 nm increases with the decrease in grain size according to the classical Hall–Petch relationship. The critical (D/d)∗ values determined for nanocrystalline Cu pillars with d = 360 and 100 nm increases with the decrease in grain size so as to conform to the same power law scaling obtained for coarse-grained Cu polycrystals. This is the first indication that the specimen size-induced softening extends from micrometer to nanometer scales as far as the dominant deformation mechanism is dislocation glide. The considerably large critical (D/d)∗ values determined for nanocrystalline Cu pillars with d = 360 and 100 nm are discussed in terms of strain continuity among neighboring grains and the generation of geometrically necessary dislocations to maintain strain continuity at the grain boundaries.|
|Rights:||© 2013 Elsevier Ltd.|
この論文は出版社版でありません。引用の際には出版社版をご確認ご利用ください。This is not the published version. Please cite only the published version.
|Appears in Collections:||Journal Articles|
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.