Mechanical properties of nanostructured materials

It is pointed out that many microstructural features like grain size and shape, their distribution, pores and their distribution, other flaws/defects and their distribution, surface condition, impurity level, second phases/dopants, stress, duration of its application and temperature affect the mechanical properties of nanocrystalline (n-) materials. Detailed studies to identify the effects of each of these variables are not available. Unequivocal as well as conflicting experimental results in this regard are summarised. The present level of theoretical understanding of the mechanical behaviour of n-materials is touched upon.