Inter- and Intra-Agglomerate Fracture in Nanocrystalline Nickel

Zhiwei Shan, J. A. Knapp, D. M. Follstaedt, E. A. Stach, J. M. K Wiezorek, and S. X. Mao

Phys. Rev. Lett. 100, 105502 – Published 12 March 2008

Abstract

In situ tensile straining transmission electron microscopy tests have been carried out on nanocrystalline Ni. Grain agglomerates (GAs) were found to form very frequently and rapidly ahead of an advancing crack with sizes much larger than the initial average grain size. High-resolution electron microscopy indicated that the GAs most probably consist of nanograins separated by low-angle grain boundaries. Furthermore, both inter- and intra-GA fractures were observed. The observations suggest that these newly formed GAs may play an important role in the formation of the dimpled fracture surfaces of nanocrystalline materials.

Received 23 August 2007

DOI:https://doi.org/10.1103/PhysRevLett.100.105502

Authors & Affiliations

Zhiwei Shan¹, J. A. Knapp², D. M. Follstaedt², E. A. Stach³, J. M. K Wiezorek¹, and S. X. Mao^1,*

¹Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
²Physical, Chemical and Nano Sciences Center, Sandia National Laboratories, Albuquerque, New Mexico 87185-1056, USA
³School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907-2044, USA

^*Corresponding author. smao@engr.pitt.edu

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Vol. 100, Iss. 10 — 14 March 2008

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