Grain Boundaries and Dislocations

Abstract
The hardness of coarse-grained materials is inversely proportional to the square root of the grain size. But as [Van Swygenhoven][1] explains in her Perspective, at nanometer scale grain sizes this relation no longer holds. Atomistic simulations are providing key insights into the structural and mechanical properties of nanocrystalline metals, shedding light on the distinct mechanism by which these materials deform. [1]: http://www.sciencemag.org/cgi/content/full/296/5565/66