  We discuss the results of N-body simulations of intermediate-mass young star
clusters (SCs) with three different metallicities (Z=0.01, 0.1 and 1 Zsun),
including metallicity-dependent stellar evolution recipes and
metallicity-dependent prescriptions for stellar winds and remnant formation.
The initial half-mass relaxation time of the simulated young SCs (~10 Myr) is
comparable to the lifetime of massive stars. We show that mass-loss by stellar
winds influences the reversal of core collapse and the expansion of the
half-mass radius. In particular, the post-collapse re-expansion of the core is
weaker for metal-poor SCs than for metal-rich SCs, because the former lose less
mass (through stellar winds) than the latter. As a consequence, the half-mass
radius expands faster in metal-poor SCs. The difference in the half-light
radius between metal-poor SCs and metal-rich SCs is (up to a factor of two)
larger than the difference in the half-mass radius.
