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Journal of Nanomaterials
Volume 2013 (2013), Article ID 912548, 8 pages
http://dx.doi.org/10.1155/2013/912548
Research Article

Microstructure and Flow Stress of Nanoscale Cu/Nb Multilayers

1State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace, Xi’an Jiaotong University, Xi’an 710049, China
2State Key Laboratory for Mechanical Behavior of Material, Xi’an Jiaotong University, Xi’an 710049, China

Received 2 April 2013; Accepted 11 May 2013

Academic Editor: Sheng-Rui Jian

Copyright © 2013 F. Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Nanoscale Cu/Nb multilayers with individual layer thicknesses of 2, 5, and 15 nm were prepared by d.c. magnetron sputtering. The cross-sectional morphologies of the multilayers were examined under transmission electron microscopy (TEM) as well as high resolution TEM, whilst the flow stresses were measured with nanoindentation. A unique cross-sectional microstructure comprising well-modulated and mixed regions was observed, causing length-scale-independent flow stresses not found in existing studies, and shear bands were absent upon plastic deformation. Built upon this unique microstructure, possible mechanisms underlying the high plastic stability and length-scale-independent flow stresses of Cu/Nb multilayers were discussed in terms of amorphous-crystalline interface and its interaction with both mixed and well-modulated regions.