Previous attempts to increase the deformability of nanomaterials, in order to reduce their tendency to fail under limited strains, have also unfortunately reduced their strength. The new experiments with hollow nanospheres show that, by combining strength and deformability, the hollow spherical geometry confers both high strength and relatively high strains at failure. The ability to endure high stress and strain is a direct result of structural hierarchy: the small grain size gives high strength, while the overall shape of the sphere distributes stress and allows the structure to withstand high strains.
"This work could only have been done with an In Situ Microscope like NCEM's, plus a quantitative mechanical testing holder like the one developed by Hysitron, Inc. and NCEM, and with hollow nanospheres like those made in the Alivisatos lab as well as the complete analysis with sophisticated computational tools provided by the Chrzan group," says Minor. "We believe the surprising results have opened a path toward much greater possible advances in structural materials at a range of scales."
|Contact: Paul Preuss|
DOE/Lawrence Berkeley National Laboratory