J. Schnitker et Dj. Srolovitz, MISFIT EFFECTS IN ADHESION CALCULATIONS, Modelling and simulation in materials science and engineering, 6(2), 1998, pp. 153-164
The work of adhesion of bimaterial interfaces is commonly computed usi
ng quantum mechanical methods in which the two materials are strained
into coherency. There is no relaxation of the coherency by the formati
on of an array of interfacial misfit dislocations, contrary to what is
commonly observed for essentially all systems ether than very thin fi
lms. In this paper, we investigate the errors introduced into the work
of adhesion associated with the assumption of coherency. Series of at
omistic simulations in two and three dimensions are performed using a
simple Lennard-Jones-type model potential. We demonstrate that the ass
umption of coherency introduces errors that increase rapidly with misf
it (for small misfit) and can easily be of the order of several tens o
f percent. We trace the source of these errors to the neglect of the e
lastic fields of misfit dislocations and to the variation in the numbe
r of bonds per unit interfacial area with misfit when coherency is ass
umed. Suggestions are made to minimize and/or correct for this error.