Nanocrystalline materials are often examined in the form of small specimens. Problems arising in testing such specimens can be classified into 3 groups: a) difficulty in the machining and handling the specimens; b) applying loading and c) strain measurements.
The present study focused attention on the mechanical properties of nanocrystalline metals measured in tensile tests. The specimens were obtained via two severe plastic deformation (SPD): a) high-pressure torsion (HPT), b) cold rolling and c) equal channel angular pressing (ECAP).
Force-displacement curves have been recorded and strain field distribution within gauge sectios and in specimen heads measured. Interpretation of the experimental curves is carried out in terms of the true and apparent values of the flow stress and elongation to fracture.