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Phoenix666 writes:

As wires of silver are made smaller and smaller, down to about 40 nanometers, they follow the expected trend: they get relatively stronger and more brittle. But earlier research by other scientists had shown that at even-more-extreme smallness—below 10 nanometers—silver does something weird. "It behaves like a Jello gelatin dessert," Sansoz say. "It becomes very soft when compressed, has very little strength, and slowly returns to its original shape."

Materials scientists hypothesize this happens because the crystals of silver are so small that most of their atoms are at the surface, with very few interior atoms. This allows diffusion of individual atoms from the surface to dominate the behavior of the metal instead of the cracking and slipping of organized lattices of atoms within. This causes these tiniest, but solid, silver crystals to have liquid-like behavior even at room temperature.

"So our question was: what's happening in the gap between 10 nanometers and 40 nanometers?" says Sansoz. "This is the first study to look at this range of diameters of nanowires."

[...] What the team of scientists found in the gap—using both an electron microscope and atomistic models on a supercomputer—is that "the two mechanisms coexist at the same time," Sansoz says. This gives silver wires in that little-explored zone both the strength of the "smaller-is-stronger" principle with the liquid-like weirdness of their smaller cousins. At this Goldilocks-like size, when defects form at the surface of the wire as it's pulled apart, "then diffusion comes in and heals the defect," Sansoz says. "So it just stretches and stretches and stretches—elongating up to two hundred percent."

More info: "Li Zhong et al. Slip-activated surface creep with room-temperature super-elongation in metallic nanocrystals," Nature Materials (2016). DOI: 10.1038/nmat4813."

There could be silver jello in your future.

Original Submission