Abstract
We show that low-density nanoporous silica monoliths (aerogels), in contrast to the case of full-density silica, exhibit pronounced time-dependent deformation during indentation at room temperature. Logarithmic indentation creep and stress relaxation are revealed, with an exponential dependency of the creep constant on the applied stress. Such time-dependent deformation is attributed to stress corrosion fracture of nanoligaments that have a large surface-to-bulk atomic fraction.
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ACKNOWLEDGMENTS
The authors thank J.H. Satcher, Jr. for providing the nanoporous silica monolith used in this study. This work was performed under the auspices of the U.S. Department of Energy (DOE) by LLNL under Contract DE-AC52-07NA27344.
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Kucheyev, S., Lord, K. & Hamza, A. Room-temperature creep of nanoporous silica. Journal of Materials Research 26, 781–784 (2011). https://doi.org/10.1557/jmr.2010.68
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DOI: https://doi.org/10.1557/jmr.2010.68