Thin films of nanoporous noble metals exhibit an interconnected, porous structure with ligament widths and pores on the order of 10 nm or higher. In this study, thin film stress measurements and in-situ nanoindentation in a transmission-electron microscope were performed to investigate the effects of nanoscale geometric confinement on the mechanicalproperties of metals and on dislocation-mediated plasticity. Although somefilms exhibit macroscopic cracking, the deformation of individual ligaments is completely ductile and clearly involves dislocation activity even in 10 nm wide ligaments. The stresses generated in these films during thermal cycling correspond to bulk stresses that approach the theoretical strength of the metal. Film stress exhibits a dependence on film thickness, even though the ligament width is much smaller and would presumably govern deformation.
|Number of pages||5|
|State||Published - Sep 2007|
Bibliographical noteFunding Information:
The authors thank Ms. Sofie Burger for assistance with measurement of ligament widths. Acknowledgment is made to the donors of the American Chemical Society Petroleum Research Fund for support of this research. TJB thanks the National Center for Electron Microscopy (NCEM) for the NCEM Visiting Scientist Fellowship that allowed this TEM work to be carried out. This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The research was also supported in part by a U.S. Department of Energy Small Business Innovation Research grant (DE-FG02-04ER83979) awarded to Hysitron, Inc., which does not constitute an endorsement by DOE of the views expressed in the article.
ASJC Scopus subject areas
- Materials Science (all)
- Engineering (all)