Cyclic Cantilever Bending of Copper Nanowhiskers

A cyclic bending test with cantilever geometry is developed for probing local mechanical properties of single crystalline Cu nanowhiskers (NWs). A lower limit for the yield stress for such whiskers is derived at approximate to 5 GPa. Since all NWs exhibit the axis parallel to the < 1 1 0 > crystallographic direction, the resolved shear stress can be calculated. The values of approximate to 2 GPa lie close to the theoretical strength limit and predict partial dislocation nucleation as the governing mechanism at the onset of plastic deformation. The yield stress is practically independent of the whisker diameter.