Résumé
The status of an on-going program of abundance determinations in A and F dwarfs in open clusters of known ages will be sum marized. So far observing time has been alloted to obtain high revolution high signal to noise echelle spectra of A and F dwarfs in several northern open clusters observable from OHP. A number of these observations have already been carried out with the ELODIE spectrograph complemented with AURELIE spectra in the red for the Alpha Persei cluster (age: 70 Myrs) and the Pleiades (135 Myrs) and Praesepe (730 Myrs). Data for 2 other clusters: IC 2391 (45 Myrs) and M7 (299 Myrs) were retrieved from the UVES archive. Determinations of abundances for several chemical elements with Z < 30 allow to set constraints on the transport processes that take place in the envelopes of these stars. Self-consistent models evolutionary models are presented for a few of these clusters.