  We present results from Tree+SPH simulations of a galaxy cluster, aimed at
studying the metal enrichment of the intra--cluster medium (ICM). The
simulation code includes a fairly advanced treatment of star formation, as well
as the release of energy feedback and detailed yields from both type-II and
type-Ia supernovae, also accurately accounting for the lifetimes of different
stellar populations. We perform simulations of a cluster with virial mass ~
3.9x 10^14 Msun, to investigate the effect of varying the feedback strength and
the stellar initial mass function (IMF). Although most of the models are able
to produce acceptable amounts of Fe mass, we find that the profiles of the iron
abundance are always steeper than observed. The [O/Fe] ratio is found to be
sub--solar for a Salpeter IMF, with [O/Fe] -0.2 at R >~ 0.1R200, whereas
increasing to super-solar values in central regions, as a result of recent star
formation. Using a top--heavier IMF gives a larger [O/Fe] over the whole
cluster, at variance with observations. On the other hand, the adoption of a
variable IMF, which becomes top-heavier at z>2, provides a roughly solar [O/Fe]
ratio. Our results indicate that our simulations still lack a feedback
mechanism which should quench star formation at low redshift and transport
metals away from the star forming regions.
