The nanohardness in the vicinity of grain boundaries in high purity Cu was investigated. It was found that the nanohardness increased upon approaching the grain boundary; the characteristic distance over which the grain boundary influenced the nano-hardness being of the order of a few microns.

Nanohardness of Copper in the Vicinity of Grain Boundaries. Y.M.Soifer, A.Verdyan, M.Kazakevich, E.Rabkin: Scripta Materialia, 2002, 47[12], 799-804