Novel methods for characterising the mechanical properties of nano whiskers

An loop test was developed for experimentally approaching the theoretical strength of whisker materials. As an example, single-crystal A1₂O₃ whiskers with diameters in the 82-320 nm range exhibited average fracture strength of 39.1 GPa with a maximum of 48.8 ± 1.8 GPa, which is close to the theoretical prediction of ~ 46 GPa. A thermal vibration test was developed for accurately determining the modulus of nanowhiskers. As an example, single-crystal W nanobelts with thicknesses down to 65 nm exhibited a size-independent modulus of about 410 GPa, which is close to that of the bulk counterparts.