ISIJ International
Online ISSN : 1347-5460
Print ISSN : 0915-1559
ISSN-L : 0915-1559
Regular Article
Transition of Deformation Mechanism with Grain Refinement in Interstitial-Free Steel
Shun ItohKasane NakazawaTetsuya MatsunagaYoshitaka MatsukawaYuhki SatohHiroaki Abe
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2014 Volume 54 Issue 7 Pages 1729-1734


To examine effects of the grain boundary (GB) and dislocation on the deformation mechanism for ultrafine-grained (UFG) and coarse-grained (CG) interstitial-free (IF) steels at room temperature, tensile tests and several types of microscopy were conducted for each steel. Atomic force microscopy revealed that the contribution of grain-boundary sliding (GBS) on deformation increased more prominently in UFG region than in CG region. Moreover, transmission electron microscopy revealed that dislocation motion was dominant in CG steel, where cell structure was formed with increasing strain. On the other hand, although dislocations moved in UFG steel, they did not tangle and piled up at GB, where interaction between GB and dislocation occurred markedly, causing significant GBS. Therefore, the dominant deformation mechanism changed from dislocation motion to GBS by decreasing grain size in IF steel.

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© 2014 by The Iron and Steel Institute of Japan
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