Interfacial force microscopy was used to determine the nano-scale elastic and plastic responses, of the (111) surfaces of single crystals, by using probes with radii ranging down to 50nm. The results showed that the stress at the plastic threshold increased with decreasing probe-tip radius. A model, for dislocation nucleation was applied, which reproduced the dependence upon tip radius.

Dislocation Nucleation at Nano-Scale Mechanical Contacts T.A.Michalske, J.E.Houston: Acta Materialia, 1998, 46[2], 391-6