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In Situ Study of Deformation Mechanisms in Sputtered Free-Standing Nanocrystalline Nickel Films

Published online by Cambridge University Press:  03 March 2011

R. Mitra ,
A. Chiou  and
J.R. Weertman
R. Mitra
Affiliation:
Department of Materials Science and Engineering, Northwestern University, Evanston, Illinios 60208
A. Chiou
Affiliation:
Department of Materials Science and Engineering, Northwestern University, Evanston, Illinios 60208
J.R. Weertman
Affiliation:
Department of Materials Science and Engineering, Northwestern University, Evanston, Illinios 60208

Abstract

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Nickel films of 1.5–10-μm thickness, produced by dc magnetron sputtering and with disperse grain size distributions peaking in the 30–60-nm range, were subject to in situ tensile straining in a transmission electron microscope. The deformation was stopped frequently, while keeping the load applied, for transmission electron microscopy observation of the internal structure. Contrast changes occurred in many of the grains between strain increments. Ample evidence was seen of dislocation activity, which appears to be the major mechanism for deformation of the samples. Dislocations were seen in grains as small as 20 nm. Parallel arrays of roughly equally spaced dislocations were observed, spaced about 5–10-nm apart. Intergranular nanovoids were found to form and grow with accompanying strain relief in neighboring grains. The results of the current study are generally consistent with previous in situ investigations and contribute to the understanding of deformation mechanisms in free-standing thin films, which may differ somewhat from those in bulk nanocrystalline materials or in films attached to a substrate.

Keywords

DislocationsNanoscaleTransmission electron microscopy (TEM)
Type
Articles
Information
Journal of Materials Research , Volume 19 , Issue 4 , April 2004 , pp. 1029 - 1037
Copyright
Copyright © Materials Research Society 2004

References

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