  In quasicrystals, there are not only conventional, but also phason
displacement fields and associated Burgers vectors. We have calculated
approximate solutions for the elastic fields induced by two-, three- and
fivefold straight screw- and edge-dislocations in infinite icosahedral
quasicrystals by means of a generalized perturbation method. Starting from the
solution for elastic isotropy in phonon and phason spaces, corrections of
higher order reflect the two-, three- and fivefold symmetry of the elastic
fields surrounding screw dislocations. The fields of special edge dislocations
display characteristic symmetries also, which can be seen from the
contributions of all orders.
