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(Funded by the U.S. Department of Energy and the National Science Foundation)
Metals get stronger as the size of the grains making up the metal gets smaller – up to a point. If the grains are smaller than 10 nanometers in diameter, the materials are weaker because, it was thought, they slide past each other like sand sliding down a dune. But researchers at Princeton University, the University of California, Berkeley, and at universities in China have shown that in samples of nickel with grain diameters as small as 3 nanometers, and under high pressures, the strength of the samples continued to increase with smaller grain sizes.
