The effect of grain size on the overall elastic and plastic properties
of nanocrystalline materials has been evaluated using the elastoplast
ic finite element method. The tensile deformation behaviour of nanocry
stalline copper(based on a unit cell model comprising 2-100 nm sized c
opper crystallites and 1 nm wide grain boundaries) has been analysed.
Assuming that the material is elastic-perfect plastic (because of the
very fine grain size), it has been shown that the yield stress increas
es and the elastic modulus decreases with a decrease in grain size. Th
ese results are consistent with the reported experimental observations
. This analysis can be used effectively to predict the mechanical beha
viour of any type of nanocrystalline material.