  The simultaneous investigation of Li and Be in stars is a powerful tool in
the study of the evolutionary mixing processes. Here, we present beryllium
abundances in stars along the whole evolutionary sequence of the open cluster
IC 4651. This cluster has a metallicity of [Fe/H] = +0.11 and an age of 1.2 or
1.7 Gyr. Abundances have been determined from high-resolution, high
signal-to-noise UVES spectra using spectrum synthesis and model atmospheres.
Lithium abundances for the same stars were determined in a previous work.
Confirming previous results, we find that the Li dip is also a Be dip. For
post-main-sequence stars, the Be dilution starts earlier within the Hertzsprung
gap than expected from classical predictions, as does the Li dilution.
Theoretical hydrodynamical models are able to reproduce well all the observed
features.
